Finding Root Categories

Article
07/18/2009

Note: The Microsoft UDDI SDK is not supported by or included in Microsoft Windows versions after Microsoft Windows Server 7. The Microsoft UDDI V3 SDK is included with Microsoft BizTalk Server. For more information about the Microsoft UDDI V3 SDK, see Microsoft BizTalk Server documentation

This topic describes how to find the root categories of a categorization scheme that is available on a UDDI server.

Purpose

This topic shows how to find the root categories of the specified categorization scheme. After finding the root categories, you can enumerate all of the categories that are related to each root category. For more information, see Finding Related Categories.

Prerequisites and Requirements

To find the root categories used in a categorization scheme, you need a categorization scheme that is used by a UDDI server. For more information, see Finding Categorization Schemes.

This example requires the following components:

.NET Framework 2.0.
Visual Studio .NET 2003 or later.
A valid UddiConnection object with an inquiry URL and an extension URL. For more information, see Initializing a Connection.
A categorization scheme that is available on a UDDI server. For more information, see Finding Categorization Schemes.

The following namespaces:

Example Code

The following Visual C# example shows how to find the root categories of a categorization scheme.

static void GetRootCategoriesExample( UddiConnection validConnection, 
                                      TModelInfo catSchemeObject,
                                      StringBuilder displayText )
{
    
    CategoryList rootCategoryList = null;
    
    Category rootCategory = new Category( catSchemeObject.TModelKey );
    
    rootCategory.RelationshipQualifiers.Add( RelationshipQualifier.root );         
    
    GetRelatedCategories rootCategories = new GetRelatedCategories( rootCategory );                
    
    try
    {
    
        rootCategoryList = rootCategories.Send( validConnection );
                    
    }
    
    catch(InvalidKeyPassedException invalidKeyPassed)
    {
    
        // Insert error-handling code for this exception.
        displayText.Append( "Invalid key passed." );

        return;
        
    }    
    
    catch(InvalidUrlPassedException badURL) 
    {
    
        // Insert error-handling code for this exception.
        displayText.Append( "Bad URL" );

        return;
        
    }

    catch( UddiException genericUDDIException)
    { 

        // Insert error-handling code for this exception.
        displayText.Append( genericUDDIException.Message );

        return;
        
    }

    catch( Exception otherException)
    {

        // Insert error-handling code for this exception.
        displayText.Append( otherException.Message );

        displayText.Append( otherException.GetType().ToString() );

        return;
    
    }
    
    CategoryValueCollection rootValues;
    
    rootValues = rootCategoryList.CategoryInfos[0].Roots;
        
    foreach(CategoryValue rootValue in rootValues)
    {
    
        displayText.Append("\r\n " + rootValue.KeyName);
        
        if( rootValues.IndexOf( rootValue ) < 1 )
        {
            
            GetChildCategoriesExample( validConnection,
                                       catSchemeObject,
                                       rootValue,
                                       displayText,
                                       3 );
                                       
        }
            
    }
          
}

The following Visual Basic .NET example shows how to find the root categories of a categorization scheme.

Sub GetRootCategoriesExample(ByVal validConnection As UddiConnection, _
                             ByVal catSchemeObject As TModelInfo, _
                             ByVal displayText As StringBuilder)

    Dim rootCategoryList As CategoryList

    Dim rootCategory As New Category(catSchemeObject.TModelKey)

    rootCategory.RelationshipQualifiers.Add(RelationshipQualifier.root)

    Dim relatedCategories As New GetRelatedCategories(rootCategory)

    Try

        rootCategoryList = relatedCategories.Send(validConnection)

    Catch invalidKeyPassed As InvalidKeyPassedException

        ' Insert error-handling code for this exception.
        displayText.Append("Invalid key passed.")

        Return

    Catch badURL As InvalidUrlPassedException

        ' Insert error-handling code for this exception.
        displayText.Append("Bad URL")

        Return

    Catch genericUDDIException As UddiException

        ' Insert error-handling code for this exception.
        displayText.Append(genericUDDIException.Message)

        Return

    Catch otherException As Exception

        ' Insert error-handling code for this exception.
        displayText.Append(otherException.Message)

        displayText.Append(otherException.GetType.ToString)

        Return

    End Try

    Dim rootCategories As CategoryValueCollection

    rootCategories = rootCategoryList.CategoryInfos(0).Roots

    Dim rootValue As CategoryValue

    For Each rootValue In rootCategories

        displayText.Append(vbCrLf + "  " + rootValue.KeyName)

    Next

End Sub

Example Result

When you run the example code, the StringBuilder object produces results that are similar to the following list. This is a list of root categories from the ntis-gov:naics:1997 categorization scheme:

ntis-gov:naics:1997
 Agriculture, Forestry, Fishing and Hunting
 Mining
 Utilities
 Construction
 Manufacturing
 Manufacturing
 Manufacturing
 Wholesale Trade
 Retail Trade
 Retail Trade
 Transportation and Warehousing
 Transportation and Warehousing
 Information
 Finance and Insurance
 Real Estate and Rental and Leasing
 Professional, Scientific, and Technical Services
 Management of Companies and Enterprises
 Administrative and Support and Waste Management and Remediation Services
 Educational Services
 Health Care and Social Assistance
 Arts, Entertainment, and Recreation
 Accommodation and Food Services
 Other Services (except Public Administration)
 Public Administration

Implementation Steps

The following sections show how to implement the example code:

Implementation Steps in C#

Create a method that accepts the following parameters:
- A valid UddiConnection object.
- A TModelInfo object. This object contains the categorization scheme with the related child categories.
- A StringBuilder object. This object contains the information about the related child categories.
```
static void GetRootCategoriesExample( UddiConnection validConnection, 
                                      TModelInfo catSchemeObject,
                                      StringBuilder displayText )
{
}
```

Create a CategoryList variable and initialize it to null. This variable will contain the results of the message from the UDDI server.

static void GetRootCategoriesExample( UddiConnection validConnection, 
                                      TModelInfo catSchemeObject,
                                      StringBuilder displayText )
{
    CategoryList rootCategoryList = null;
}

Create an instance of the Category class using the Category constructor method with the TModelKey passed to the method. This object will be used to create the message that is sent to the UDDI server to find the root categories.

static void GetRootCategoriesExample( UddiConnection validConnection, 
                                      TModelInfo catSchemeObject,
                                      StringBuilder displayText )
{

    CategoryList rootCategoryList = null;

    Category rootCategory = new Category( catSchemeObject.TModelKey );
}

Using the Add method, set the RelationshipQualifiers property of the Category object to the root member of the RelationshipQualifier enumeration.

static void GetRootCategoriesExample( UddiConnection validConnection, 
                                      TModelInfo catSchemeObject,
                                      StringBuilder displayText )
{

    CategoryList rootCategoryList = null;

    Category rootCategory = new Category( catSchemeObject.TModelKey );

    rootCategory.RelationshipQualifiers.Add( RelationshipQualifier.root );


}

Create an instance of the GetRelatedCategories class using the GetRelatedCategories constructor method with the Category object that was created in the previous step. This object is the message that will be sent to the UDDI server.

static void GetRootCategoriesExample( UddiConnection validConnection, 
                                      TModelInfo catSchemeObject,
                                      StringBuilder displayText )
{

    CategoryList rootCategoryList = null;

    Category rootCategory = new Category( catSchemeObject.TModelKey );

    rootCategory.RelationshipQualifiers.Add( RelationshipQualifier.root );         

    GetRelatedCategories rootCategories = new GetRelatedCategories( rootCategory );                



}

Transmit the request to the UDDI server by using the Send method with the UddiConnection object passed into the method. The CategoryList variable receives the results of the request.

static void GetRootCategoriesExample( UddiConnection validConnection, 
                                      TModelInfo catSchemeObject,
                                      StringBuilder displayText )
{

    CategoryList rootCategoryList = null;

    Category rootCategory = new Category( catSchemeObject.TModelKey );

    rootCategory.RelationshipQualifiers.Add( RelationshipQualifier.root );         

    GetRelatedCategories rootCategories = new GetRelatedCategories( rootCategory );                

    rootCategoryList = rootCategories.Send( validConnection );



}

Handle any exceptions that may occur by using a try-catch statement. The example code shows some exceptions that you might want to handle. Wrap the request in the try statement and handle any exceptions in the catch statement.

static void GetRootCategoriesExample( UddiConnection validConnection, 
                                      TModelInfo catSchemeObject,
                                      StringBuilder displayText )
{

    CategoryList rootCategoryList = null;

    Category rootCategory = new Category( catSchemeObject.TModelKey );

    rootCategory.RelationshipQualifiers.Add( RelationshipQualifier.root );         

    GetRelatedCategories rootCategories = new GetRelatedCategories( rootCategory );                

    try
    {

        rootCategoryList = rootCategories.Send( validConnection );

    }

    catch(InvalidKeyPassedException invalidKeyPassed)
    {

        // Insert error-handling code for this exception.
        displayText.Append( "Invalid key passed." );

        return;

    }    

    catch(InvalidUrlPassedException badURL) 
    {

        // Insert error-handling code for this exception.
        displayText.Append( "Bad URL" );

        return;

    }

    catch( UddiException genericUDDIException)
    { 

        // Insert error-handling code for this exception.
        displayText.Append( genericUDDIException.Message );

        return;

    }

    catch( Exception otherException)
    {

        // Insert error-handling code for this exception.
        displayText.Append( otherException.Message );

        displayText.Append( otherException.GetType().ToString() );

        return;

    }



}

Create a CategoryValueCollection variable and initialize it to null. This variable will contain the root category collection from the CategoryList variable.

static void GetRootCategoriesExample( UddiConnection validConnection, 
                                      TModelInfo catSchemeObject,
                                      StringBuilder displayText )
{

    CategoryList rootCategoryList = null;

    Category rootCategory = new Category( catSchemeObject.TModelKey );

    rootCategory.RelationshipQualifiers.Add( RelationshipQualifier.root );         

    GetRelatedCategories rootCategories = new GetRelatedCategories( rootCategory );                

    try
    {

        rootCategoryList = rootCategories.Send( validConnection );

    }

    catch(InvalidKeyPassedException invalidKeyPassed)
    {

        // Insert error-handling code for this exception.
        displayText.Append( "Invalid key passed." );

        return;

    }    

    catch(InvalidUrlPassedException badURL) 
    {

        // Insert error-handling code for this exception.
        displayText.Append( "Bad URL" );

        return;

    }

    catch( UddiException genericUDDIException)
    { 

        // Insert error-handling code for this exception.
        displayText.Append( genericUDDIException.Message );

        return;

    }

    catch( Exception otherException)
    {

        // Insert error-handling code for this exception.
        displayText.Append( otherException.Message );

        displayText.Append( otherException.GetType().ToString() );

        return;

    }

    CategoryValueCollection rootValues;



}

Set the CategoryValueCollection variable to the CategoryInfos property of the CategoryList object. The CategoryInfos property is a property of the Roots property.

Note

The CategoryList variable contains only one collection of root categories because the example finds the root categories of a single categorization scheme. If you were to specify multiple categorization schemes to search, the CategoryInfos property would contain a collection array of root categories for each specified categorization scheme. You would then iterate the collection array to find each collection for each specified category.

To find root categories of multiple categorization schemes, create an instance of the Category class using the Category constructor method with the TModelKey of each categorization scheme. Add each Category to a CategoryCollection object and then use the GetRelatedCategories constructor method with the CategoryCollection object to create an instance of the GetRelatedCategories class. For more information, see GetRelatedCategories.

static void GetRootCategoriesExample( UddiConnection validConnection, 
                                      TModelInfo catSchemeObject,
                                      StringBuilder displayText )
{
    
    CategoryList rootCategoryList = null;
    
    Category rootCategory = new Category( catSchemeObject.TModelKey );
    
    rootCategory.RelationshipQualifiers.Add( RelationshipQualifier.root );         
    
    GetRelatedCategories rootCategories = new GetRelatedCategories( rootCategory );                
    
    try
    {
    
        rootCategoryList = rootCategories.Send( validConnection );
                    
    }
    
    catch(InvalidKeyPassedException invalidKeyPassed)
    {
    
        // Insert error-handling code for this exception.
        displayText.Append( "Invalid key passed." );

        return;
        
    }    
    
    catch(InvalidUrlPassedException badURL) 
    {
    
        // Insert error-handling code for this exception.
        displayText.Append( "Bad URL" );

        return;
        
    }

    catch( UddiException genericUDDIException)
    { 

        // Insert error-handling code for this exception.
        displayText.Append( genericUDDIException.Message );

        return;
        
    }

    catch( Exception otherException)
    {

        // Insert error-handling code for this exception.
        displayText.Append( otherException.Message );

        displayText.Append( otherException.GetType().ToString() );

        return;
    
    }
    
    CategoryValueCollection rootValues;
    
    rootValues = rootCategoryList.CategoryInfos[0].Roots;
        
        
  
}

Iterate through the CategoryValueCollection object to get information about the root categories. In this example, the name of each root category is added to the StringBuilder object that displays information about root categories.

static void GetRootCategoriesExample( UddiConnection validConnection, 
                                      TModelInfo catSchemeObject,
                                      StringBuilder displayText )
{

    CategoryList rootCategoryList = null;

    Category rootCategory = new Category( catSchemeObject.TModelKey );

    rootCategory.RelationshipQualifiers.Add( RelationshipQualifier.root );         

    GetRelatedCategories rootCategories = new GetRelatedCategories( rootCategory );                

    try
    {

        rootCategoryList = rootCategories.Send( validConnection );

    }

    catch(InvalidKeyPassedException invalidKeyPassed)
    {

        // Insert error-handling code for this exception.
        displayText.Append( "Invalid key passed." );

        return;

    }    

    catch(InvalidUrlPassedException badURL) 
    {

        // Insert error-handling code for this exception.
        displayText.Append( "Bad URL" );

        return;

    }

    catch( UddiException genericUDDIException)
    { 

        // Insert error-handling code for this exception.
        displayText.Append( genericUDDIException.Message );

        return;

    }

    catch( Exception otherException)
    {

        // Insert error-handling code for this exception.
        displayText.Append( otherException.Message );

        displayText.Append( otherException.GetType().ToString() );

        return;

    }

    CategoryValueCollection rootValues;

    rootValues = rootCategoryList.CategoryInfos[0].Roots;

    foreach(CategoryValue rootValue in rootValues)
    {

        displayText.Append("\r\n " + rootValue.KeyName);

    }

}

Optional. To find the related categories of each root category, you can create an optional method that finds the related categories and then recursively call this optional method. For more information about creating a method that finds root categories, see, Finding Related Categories. This example calls the optional method for the first root category in the collection.

static void GetRootCategoriesExample( UddiConnection validConnection, 
                                      TModelInfo catSchemeObject,
                                      StringBuilder displayText )
{

    CategoryList rootCategoryList = null;

    Category rootCategory = new Category( catSchemeObject.TModelKey );

    rootCategory.RelationshipQualifiers.Add( RelationshipQualifier.root );         

    GetRelatedCategories rootCategories = new GetRelatedCategories( rootCategory );                

    try
    {

        rootCategoryList = rootCategories.Send( validConnection );

    }

    catch(InvalidKeyPassedException invalidKeyPassed)
    {

        // Insert error-handling code for this exception.
        displayText.Append( "Invalid key passed." );

        return;

    }    

    catch(InvalidUrlPassedException badURL) 
    {

        // Insert error-handling code for this exception.
        displayText.Append( "Bad URL" );

        return;

    }

    catch( UddiException genericUDDIException)
    { 

        // Insert error-handling code for this exception.
        displayText.Append( genericUDDIException.Message );

        return;

    }

    catch( Exception otherException)
    {

        // Insert error-handling code for this exception.
        displayText.Append( otherException.Message );

        displayText.Append( otherException.GetType().ToString() );

        return;

    }

    CategoryValueCollection rootValues;
    rootValues = rootCategoryList.CategoryInfos[0].Roots;

    foreach(CategoryValue rootValue in rootValues)
    {

        displayText.Append("\r\n " + rootValue.KeyName);

        if( rootValues.IndexOf( rootValue ) < 1 )
        {

            GetChildCategoriesExample( validConnection,
                                       catSchemeObject,
                                       rootValue,
                                       displayText,
                                       3 );

        }

    }

}

Implementation Steps In Visual Basic .NET

Create a method that accepts the following parameters:
- A valid UddiConnection object.
- A TModelInfo object. This object contains the categorization scheme that contains the specified category with the child categories that you want to find.
- A StringBuilder object. This object contains the information about the child categories.
```
Sub GetRootCategoriesExample(ByVal validConnection As UddiConnection, _
                             ByVal catSchemeObject As TModelInfo, _
                             ByVal displayText As StringBuilder)
End Sub
```

Create a CategoryList variable that will contain the results of the message from the UDDI server.

Sub GetRootCategoriesExample(ByVal validConnection As UddiConnection, _
                             ByVal catSchemeObject As TModelInfo, _
                             ByVal displayText As StringBuilder)
    Dim rootCategoryList As CategoryList
End Sub

Create an instance of the Category class using the Category constructor method with the TModelKey passed to the method. This object will be used to create the message that is sent to the UDDI server to find the root categories.

Sub GetRootCategoriesExample(ByVal validConnection As UddiConnection, _
                             ByVal catSchemeObject As TModelInfo, _
                             ByVal displayText As StringBuilder)
    Dim rootCategoryList As CategoryList
    Dim rootCategory As New Category(catSchemeObject.TModelKey)
End Sub

Using the Add method, set the RelationshipQualifiers property of the Category object to the root member of the RelationshipQualifier enumeration.

Sub GetRootCategoriesExample(ByVal validConnection As UddiConnection, _
                             ByVal catSchemeObject As TModelInfo, _
                             ByVal displayText As StringBuilder)

    Dim rootCategoryList As CategoryList

    Dim rootCategory As New Category(catSchemeObject.TModelKey)

    rootCategory.RelationshipQualifiers.Add(RelationshipQualifier.root)



End Sub

Create an instance of the GetRelatedCategories class using the GetRelatedCategories constructor method with the Category object that was created in the previous step. This object is the message that will be sent to the UDDI server.

Sub GetRootCategoriesExample(ByVal validConnection As UddiConnection, _
                             ByVal catSchemeObject As TModelInfo, _
                             ByVal displayText As StringBuilder)

    Dim rootCategoryList As CategoryList

    Dim rootCategory As New Category(catSchemeObject.TModelKey)

    rootCategory.RelationshipQualifiers.Add(RelationshipQualifier.root)

    Dim relatedCategories As New GetRelatedCategories(rootCategory)



End Sub

Transmit the request to the UDDI server by using the Send method with the UddiConnection object passed into the method. The CategoryList variable receives the results of the request.

Sub GetRootCategoriesExample(ByVal validConnection As UddiConnection, _
                             ByVal catSchemeObject As TModelInfo, _
                             ByVal displayText As StringBuilder)

    Dim rootCategoryList As CategoryList

    Dim rootCategory As New Category(catSchemeObject.TModelKey)

    rootCategory.RelationshipQualifiers.Add(RelationshipQualifier.root)

    Dim relatedCategories As New GetRelatedCategories(rootCategory)

    rootCategoryList = relatedCategories.Send(validConnection)



End Sub

Sub GetRootCategoriesExample(ByVal validConnection As UddiConnection, _
                             ByVal catSchemeObject As TModelInfo, _
                             ByVal displayText As StringBuilder)

    Dim rootCategoryList As CategoryList

    Dim rootCategory As New Category(catSchemeObject.TModelKey)

    rootCategory.RelationshipQualifiers.Add(RelationshipQualifier.root)

    Dim relatedCategories As New GetRelatedCategories(rootCategory)

    Try

        rootCategoryList = relatedCategories.Send(validConnection)

    Catch invalidKeyPassed As InvalidKeyPassedException

        ' Insert error-handling code for this exception.
        displayText.Append("Invalid key passed.")

        Return

    Catch badURL As InvalidUrlPassedException

        ' Insert error-handling code for this exception.
        displayText.Append("Bad URL")

        Return

    Catch genericUDDIException As UddiException

        ' Insert error-handling code for this exception.
        displayText.Append(genericUDDIException.Message)

        Return

    Catch otherException As Exception

        ' Insert error-handling code for this exception.
        displayText.Append(otherException.Message)

        displayText.Append(otherException.GetType.ToString)

        Return

    End Try



End Sub

Create a CategoryValueCollection variable and initialize it to null. This variable will contain the root category collection from the CategoryList variable.

Sub GetRootCategoriesExample(ByVal validConnection As UddiConnection, _
                             ByVal catSchemeObject As TModelInfo, _
                             ByVal displayText As StringBuilder)

    Dim rootCategoryList As CategoryList

    Dim rootCategory As New Category(catSchemeObject.TModelKey)

    rootCategory.RelationshipQualifiers.Add(RelationshipQualifier.root)

    Dim relatedCategories As New GetRelatedCategories(rootCategory)

    Try

        rootCategoryList = relatedCategories.Send(validConnection)

    Catch invalidKeyPassed As InvalidKeyPassedException

        ' Insert error-handling code for this exception.
        displayText.Append("Invalid key passed.")

        Return

    Catch badURL As InvalidUrlPassedException

        ' Insert error-handling code for this exception.
        displayText.Append("Bad URL")

        Return

    Catch genericUDDIException As UddiException

        ' Insert error-handling code for this exception.
        displayText.Append(genericUDDIException.Message)

        Return

    Catch otherException As Exception

        ' Insert error-handling code for this exception.
        displayText.Append(otherException.Message)

        displayText.Append(otherException.GetType.ToString)

        Return

    End Try

    Dim rootCategories As CategoryValueCollection



End Sub

Set the CategoryValueCollection variable to the Roots property of the CategoryInfos property of the CategoryList object.

Note

The CategoryList variable contains only one collection of root categories because the example finds the root categories of single categorization scheme. If you specify multiple categorization schemes to search, the CategoryInfos property would contain a collection array of root categories for each specified categorization scheme. You would then iterate the collection array to find each collection for each specified category.

To find root categories of multiple categorization schemes, create an instance of the Category class using the Category constructor method with the TModelKey of each categorization scheme. Add each Category to a CategoryCollection object and then use the GetRelatedCategories constructor method with the CategoryCollection object to create an instance of the GetRelatedCategories class. For more information, see GetRelatedCategories.

Sub GetRootCategoriesExample(ByVal validConnection As UddiConnection, _
                             ByVal catSchemeObject As TModelInfo, _
                             ByVal displayText As StringBuilder)

    Dim rootCategoryList As CategoryList

    Dim rootCategory As New Category(catSchemeObject.TModelKey)

    rootCategory.RelationshipQualifiers.Add(RelationshipQualifier.root)

    Dim relatedCategories As New GetRelatedCategories(rootCategory)

    Try

        rootCategoryList = relatedCategories.Send(validConnection)

    Catch invalidKeyPassed As InvalidKeyPassedException

        ' Insert error-handling code for this exception.
        displayText.Append("Invalid key passed.")

        Return

    Catch badURL As InvalidUrlPassedException

        ' Insert error-handling code for this exception.
        displayText.Append("Bad URL")

        Return

    Catch genericUDDIException As UddiException

        ' Insert error-handling code for this exception.
        displayText.Append(genericUDDIException.Message)

        Return

    Catch otherException As Exception

        ' Insert error-handling code for this exception.
        displayText.Append(otherException.Message)

        displayText.Append(otherException.GetType.ToString)

        Return

    End Try

    Dim rootCategories As CategoryValueCollection

    rootCategories = rootCategoryList.CategoryInfos(0).Roots



End Sub

Sub GetRootCategoriesExample(ByVal validConnection As UddiConnection, _
                             ByVal catSchemeObject As TModelInfo, _
                             ByVal displayText As StringBuilder)

    Dim rootCategoryList As CategoryList

    Dim rootCategory As New Category(catSchemeObject.TModelKey)

    rootCategory.RelationshipQualifiers.Add(RelationshipQualifier.root)

    Dim relatedCategories As New GetRelatedCategories(rootCategory)

    Try

        rootCategoryList = relatedCategories.Send(validConnection)

    Catch invalidKeyPassed As InvalidKeyPassedException

        ' Insert error-handling code for this exception.
        displayText.Append("Invalid key passed.")

        Return

    Catch badURL As InvalidUrlPassedException

        ' Insert error-handling code for this exception.
        displayText.Append("Bad URL")

        Return

    Catch genericUDDIException As UddiException

        ' Insert error-handling code for this exception.
        displayText.Append(genericUDDIException.Message)

        Return

    Catch otherException As Exception

        ' Insert error-handling code for this exception.
        displayText.Append(otherException.Message)

        displayText.Append(otherException.GetType.ToString)

        Return

    End Try

    Dim rootCategories As CategoryValueCollection

    rootCategories = rootCategoryList.CategoryInfos(0).Roots

    Dim rootValue As CategoryValue

    For Each rootValue In rootCategories

        displayText.Append(vbCrLf + "  " + rootValue.KeyName)

    Next

End Sub

Optional. To find the related categories of each root category, you can create an optional method that finds the related categories and then recursively call this new method. For more information about creating a method that finds root categories, Finding Related Categories. This example calls the optional method for the first root category in the collection.

Sub GetRootCategoriesExample(ByVal validConnection As UddiConnection, _
                             ByVal catSchemeObject As TModelInfo, _
                             ByVal displayText As StringBuilder)

    Dim rootCategoryList As CategoryList

    Dim rootCategory As New Category(catSchemeObject.TModelKey)

    rootCategory.RelationshipQualifiers.Add(RelationshipQualifier.root)

    Dim relatedCategories As New GetRelatedCategories(rootCategory)

    Try

        rootCategoryList = relatedCategories.Send(validConnection)

    Catch invalidKeyPassed As InvalidKeyPassedException

        ' Insert error-handling code for this exception.
        displayText.Append("Invalid key passed.")

        Return

    Catch badURL As InvalidUrlPassedException

        ' Insert error-handling code for this exception.
        displayText.Append("Bad URL")

        Return

    Catch genericUDDIException As UddiException

        ' Insert error-handling code for this exception.
        displayText.Append(genericUDDIException.Message)

        Return

    Catch otherException As Exception

        ' Insert error-handling code for this exception.
        displayText.Append(otherException.Message)

        displayText.Append(otherException.GetType.ToString)

        Return

    End Try

    Dim rootCategories As CategoryValueCollection

    rootCategories = rootCategoryList.CategoryInfos(0).Roots

    Dim rootValue As CategoryValue

    For Each rootValue In rootCategories

        displayText.Append(vbCrLf + "  " + rootValue.KeyName)

        If rootCategories.IndexOf(rootValue) < 1 Then

            GetChildCategoriesExample(validConnection, _
                                      catSchemeObject, _
                                      rootValue, _
                                      displayText, _
                                      3)

        End If

    Next

End Sub

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Finding Root Categories

Purpose

Prerequisites and Requirements

Example Code

Example Result

Implementation Steps

Implementation Steps in C#

Implementation Steps In Visual Basic .NET

See Also

Reference

Concepts

Additional resources