GetExpression 方法

Returns a String that contains the expression for the specified property. Null means no expression is assigned.

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

语法

声明
Function GetExpression ( _
    propertyName As String _
) As String
用法
Dim instance As IDTSPropertiesProvider
Dim propertyName As String
Dim returnValue As String

returnValue = instance.GetExpression(propertyName)

string GetExpression(
    string propertyName
)

String^ GetExpression(
    String^ propertyName
)

abstract GetExpression : 
        propertyName:string -> string 

function GetExpression(
    propertyName : String
) : String

参数

• propertyName
  类型：System. . :: . .String
  The name of the property whose expression you want to see.

返回值

类型：System. . :: . .String
A String that contains the expression used to evaluate the property.

注释

The propertyName can be any property available on the object.

示例

The ConnectionManager class inherits from the IDTSPropertiesProvider interface. The following code example shows the ConnectionManager class using the SetExpression and GetExpression methods that it inherited.

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 on the property.
            DTSExecResult valResult = pkg.Validate(myConns, null, null, null);
            
            // Now that the value has been set, retrieve the value
            // and the expression.
            myValue = myConnMgr.Properties["RetainSameConnection"].GetValue(myConnMgr);
            mySValue = myValue.ToString();
            String myExpression = myConnMgr.Properties["RetainSameConnection"].GetExpression(myConnMgr);
            String mySExpression = myExpression.ToString();
            Console.WriteLine("value and expression is {0}, {1}", mySValue, mySExpression); 
        }
    }
}

Imports System
Imports System.Collections.Generic
Imports System.Text
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 on the property.
        Dim valResult As DTSExecResult = pkg.Validate(myConns, Nothing, Nothing, Nothing)

        ' Now that the value has been set, retrieve the value
        ' and the expression.
        myValue = myConnMgr.Properties("RetainSameConnection").GetValue(myConnMgr)
        mySValue = myValue.ToString()
        Dim myExpression As String = myConnMgr.Properties("RetainSameConnection").GetExpression(myConnMgr)
        Dim mySExpression As String = myExpression.ToString()
        Console.WriteLine("value and expression is {0}, {1}", mySValue, mySExpression) 
        End Sub
    End Class
End Namespace

Sample Output:

has RetainSameConnection? True

value before is False

value and expression is True, true

请参阅

参考

IDTSPropertiesProvider 接口

Microsoft.SqlServer.Dts.Runtime 命名空间