SetExpression 方法

Assigns the specified expression to the object. Specify nullNothingnullptrunitnull 引用（在 Visual Basic 中为 Nothing） to remove an existing expression from the property.

命名空间：  Microsoft.SqlServer.Dts.Runtime
程序集：  Microsoft.SqlServer.ManagedDTS（在 Microsoft.SqlServer.ManagedDTS.dll 中）

语法

声明
Public Sub SetExpression ( _
    o As Object, _
    expression As String _
)
用法
Dim instance As DtsProperty
Dim o As Object
Dim expression As String

instance.SetExpression(o, expression)

public void SetExpression(
    Object o,
    string expression
)

public:
void SetExpression(
    Object^ o, 
    String^ expression
)

member SetExpression : 
        o:Object * 
        expression:string -> unit 

public function SetExpression(
    o : Object, 
    expression : String
)

参数

• o
  类型：System. . :: . .Object
  The name of the object to which to assign the expression.

• expression
  类型：System. . :: . .String
  The expression.

注释

All the containers and several additional objects inherit from IDTSPropertiesProvider, which is the interface that provides the GetExpression and SetExpression methods.

示例

The ConnectionManager is one class that inherits from IDTSPropertiesProvider and implements the SetExpression method. The following code example shows how the SetExpression method is used. The expression sets the value of a property that is specific to a connection manager. The properties that are unique to the connection manager are contained in the Properties collection.

using System;
using System.Collections.Generic;
using System.Text;
using Microsoft.SqlServer.Dts.Runtime;

namespace ConnMgr_Properties_Collection
{
    class Program
    {
        static void Main(string[] args)
        {
            // The package is one of the SSIS Samples.
            string mySample = @"C:\Program Files\Microsoft SQL Server\100\Samples\Integration Services\Package Samples\CalculatedColumns Sample\CalculatedColumns\CalculatedColumns.dtsx";

            // Create an application and load the sample.
            Application app = new Application();
            Package pkg = app.LoadPackage(mySample, null);
            Connections myConns = pkg.Connections;

            // Get the Properties collection from the connection manager.
            ConnectionManager myConnMgr = myConns[0];
            DtsProperties connProperties = myConnMgr.Properties;

            // View information about the RetainSameConnection property
            // before setting it using the SetExpression method.
            Boolean hasProperty = connProperties.Contains("RetainSameConnection");
            Console.WriteLine("has RetainSameConnection? {0}", hasProperty);
            Object myValue = myConnMgr.Properties["RetainSameConnection"].GetValue(myConnMgr);
            String mySValue = myValue.ToString();
            Console.WriteLine("value before is {0}", mySValue);String myTrueString = "true";

            // Use SetExpression to set the value to true.
            myConnMgr.Properties["RetainSameConnection"].SetExpression(myConnMgr, myTrueString);
            
            // Validate the package to set the expression onto the property.
            DTSExecResult valResult = pkg.Validate(myConns, null, null, null);
            
            // Now that the value has been set, retrieve it.
            myValue = myConnMgr.Properties["RetainSameConnection"].GetValue(myConnMgr);
            mySValue = myValue.ToString();
            Console.WriteLine("value after is {0}", mySValue); 
        }
    }
}

Imports Microsoft.SqlServer.Dts.Runtime
 
Namespace ConnMgr_Properties_Collection
    Class Program
        Shared  Sub Main(ByVal args() As String)
        ' The package is one of the SSIS Samples.
        Dim mySample As String = "C:\Program Files\Microsoft SQL Server\100\Samples\Integration Services\Package Samples\CalculatedColumns Sample\CalculatedColumns\CalculatedColumns.dtsx"
        
        ' Create an application and load the sample.
        Dim app As New Application()
        Dim pkg As Package = app.LoadPackage(mySample, Nothing)
        Dim myConns As Connections = pkg.Connections
        
        ' Get the Properties collection from the connection manager.
        Dim myConnMgr As ConnectionManager = myConns(0)
        Dim connProperties As DtsProperties = myConnMgr.Properties
        
        ' View information about the RetainSameConnection property
        ' before setting it using the SetExpression method.
        Dim hasProperty As [Boolean] = connProperties.Contains("RetainSameConnection")
        Console.WriteLine("has RetainSameConnection? {0}", hasProperty)
        Dim myValue As [Object] = myConnMgr.Properties("RetainSameConnection").GetValue(myConnMgr)
        Dim mySValue As String = myValue.ToString()
        Console.WriteLine("value before is {0}", mySValue)
        Dim myTrueString As String = "true"
        
        ' Use SetExpression to set the value to true.
        myConnMgr.Properties("RetainSameConnection").SetExpression(myConnMgr, myTrueString)
        
        ' Validate the package to set the expression onto the property.
        Dim valResult As DTSExecResult = pkg.Validate(myConns, Nothing, Nothing, Nothing)
        
        ' Now that the value has been set, retrieve it.
        myValue = myConnMgr.Properties("RetainSameConnection").GetValue(myConnMgr)
        mySValue = myValue.ToString()
        Console.WriteLine("value after is {0}", mySValue)
        End Sub
    End Class
End Namespace

Sample Output:

has RetainSameConnection? True

value before is False

value after is True

请参阅

参考

DtsProperty 类

Microsoft.SqlServer.Dts.Runtime 命名空间