QueryExpression sample code

Artigo
12/05/2024

To try using QueryExpression with C#, you can use the OutputQueryExpression static method in this article by adapting the Quickstart: Execute an SDK for .NET request (C#).

Note

See Paging Cookie example for sample code to retrieve data in pages.

You can use the following OutputQueryExpression static method to test QueryExpression queries in a console application.

The OutputQueryExpression method demonstrates how to use the QueryExpression class and the IOrganizationService.RetrieveMultiple method to return an EntityCollection containing the requested data.

The OutputQueryExpression method depends on the ConsoleTables NuGet package and requires that all all LinkEntity instances that contain columns specify an EntityAlias.

/// <summary>
/// Renders the output of a query in a table for a console application
/// </summary>
/// <param name="service">The authenticated IOrganizationService instance to use.</param>
/// <param name="query">The query to use</param>
/// <exception cref="Exception">
/// OutputQueryExpression requires all LinkEntity instances that contain columns specify an EntityAlias property.
/// </exception>
static void OutputQueryExpression(IOrganizationService service, QueryExpression query)
{
    //Retrieve the data
    EntityCollection entityCollection = service.RetrieveMultiple(query: query);

    //Get column names from the query
    var columns = GetQueryExpressionColumns(query);

    // Create the table using https://www.nuget.org/packages/ConsoleTables/2.5.0
    var table = new ConsoleTables.ConsoleTable(columns.ToArray());

    // Add the rows of the table
    entityCollection.Entities.ToList().ForEach(entity =>
    {
        table.Rows.Add(GetRowValues(columns, entity).ToArray());
    });

    // Write the table to the console
    table.Write();

    // Get a list of column names from the query
    List<string> GetQueryExpressionColumns(QueryExpression query)
    {
        List<string> columns = new();

        columns.AddRange(GetColumns(query.ColumnSet));

        foreach (LinkEntity linkEntity in query.LinkEntities)
        {
            columns.AddRange(GetLinkEntityColumns(linkEntity));
        }

        return columns;
    }

    // Get column names from any linked tables
    List<string> GetLinkEntityColumns(LinkEntity linkEntity)
    {
        if (string.IsNullOrWhiteSpace(linkEntity.EntityAlias))
        {
            if (linkEntity.Columns.Columns.Count != 0)
            {
                string message = "OutputQueryExpressionRequest requires all ";
                message += "LinkEntity instances that contain columns ";
                message += "specify an EntityAlias property.";

                throw new Exception(message);
            }
        }

        List<string> columns = new();

        columns.AddRange(GetColumns(linkEntity.Columns, linkEntity.EntityAlias));

        foreach (LinkEntity le in linkEntity.LinkEntities)
        {
            columns.AddRange(GetColumns(le.Columns, le.EntityAlias));
        }
        return columns;
    }

    // Get columns from a columnset
    List<string> GetColumns(ColumnSet columnset, string alias = null)
    {
        List<string> columns = new();

        foreach (string column in columnset.Columns)
        {
            columns.Add(string.IsNullOrWhiteSpace(alias) ? column : $"{alias}.{column}");
        }

        foreach (XrmAttributeExpression item in columnset.AttributeExpressions)
        {
            columns.Add(item.Alias ?? item.AttributeName);
        }

        return columns;
    }

    // Get the values of a row as strings
    List<string> GetRowValues(List<string> columns, Entity entity)
    {
        List<string> values = new();
        columns.ForEach(column =>
        {
            if (entity.Attributes.ContainsKey(column))
            {
                // Use the formatted value if it available
                if (entity.FormattedValues.ContainsKey(column))
                {
                    values.Add($"{entity.FormattedValues[column]}");
                }
                else
                {
                    // When an alias is used, the Aliased value must be converted
                    if (entity.Attributes[column] is AliasedValue aliasedValue)
                    {
                        // When an EntityReference doesn't have a Name, show the Id
                        if (aliasedValue.Value is EntityReference lookup &&
                        string.IsNullOrWhiteSpace(lookup.Name))
                        {
                            values.Add($"{lookup.Id:B}");
                        }
                        else
                        {
                            values.Add($"{aliasedValue.Value}");
                        }
                    }
                    else
                    {
                        // Use the simple attribute value
                        values.Add($"{entity.Attributes[column]}");
                    }
                }
            }
            // Null values are not in the Attributes collection
            else
            {
                values.Add("NULL");
            }

        });
        return values;
    }
}

Update SDK for .NET quick start sample

You can adapt the Quick Start: Execute an SDK for .NET request (C#) sample to test queries with the following steps:

Install the ConsoleTables NuGet package

Add the following using statements at the top of the program.cs file

using Microsoft.Xrm.Sdk;
using Microsoft.Xrm.Sdk.Query;
using System.Text;
using System.Xml.Linq;

Copy and paste the OutputQueryExpression method below the Main method.

Edit the Main method to set your query and use the OutputQueryExpression method.

    static void Main(string[] args)
    {
        using (ServiceClient serviceClient = new(connectionString))
        {
            if (serviceClient.IsReady)
            {
                //WhoAmIResponse response = 
                //    (WhoAmIResponse)serviceClient.Execute(new WhoAmIRequest());

                //Console.WriteLine("User ID is {0}.", response.UserId);

                 QueryExpression query = new("account")
                 {
                    TopCount = 5,
                    ColumnSet = new ColumnSet(
                       "accountclassificationcode", 
                       "createdby", 
                       "createdon", 
                       "name")
                 };

                OutputQueryExpression(serviceClient, query);
            }
            else
            {
                Console.WriteLine(
                    "A web service connection was not established.");
            }
        }

        // Pause the console so it does not close.
        Console.WriteLine("Press the <Enter> key to exit.");
        Console.ReadLine();
    }

Read the following important information about using a connection string in application code.

Important

Microsoft recommends that you use the most secure authentication flow available. The authentication flow described in this article requires a very high degree of trust in the application, and carries risks that are not present in other flows. You should only use this flow when other more secure flows, such as managed identities, aren't viable.

When you run the program using the OutputQueryExpression method, the output should look like this:

 ---------------------------------------------------------------------------------------------------------
 | accountclassificationcode | createdby          | createdon          | name                             |
 ---------------------------------------------------------------------------------------------------------
 | Default Value             | FirstName LastName | 3/25/2023 10:42 AM | Litware, Inc. (sample)           |
 ---------------------------------------------------------------------------------------------------------
 | Default Value             | FirstName LastName | 3/25/2023 10:42 AM | Adventure Works (sample)         |
 ---------------------------------------------------------------------------------------------------------
 | Default Value             | FirstName LastName | 3/25/2023 10:42 AM | Fabrikam, Inc. (sample)          |
 ---------------------------------------------------------------------------------------------------------
 | Default Value             | FirstName LastName | 3/25/2023 10:42 AM | Blue Yonder Airlines (sample)    |
 ---------------------------------------------------------------------------------------------------------
 | Default Value             | FirstName LastName | 3/25/2023 10:42 AM | City Power & Light (sample)      |
 ---------------------------------------------------------------------------------------------------------

Query data using QueryExpression Sample: Retrieve multiple with the QueryExpression class Sample: Use QueryExpression with a paging cookie

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QueryExpression sample code

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QueryExpression sample code

Update SDK for .NET quick start sample

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