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RunWorkerCompletedEventArgs.Result Property

Gets a value that represents the result of an asynchronous operation.

Namespace:  System.ComponentModel
Assembly:  System (in System.dll)

public Object Result { get; }

Property Value

Type: System.Object
An Object representing the result of an asynchronous operation.

ExceptionCondition
TargetInvocationException

Error is not null. The InnerException property holds a reference to Error.

InvalidOperationException

Cancelled is true.

Your RunWorkerCompleted event handler should always check the Error and Cancelled properties before accessing the Result property. If an exception was raised or if the operation was canceled, accessing the Result property raises an exception.

The following code example demonstrates the use of the RunWorkerCompleted event to handle the result of an asynchronous operation. This code example is part of a larger example provided for the BackgroundWorker class.

// This event handler deals with the results of the 
// background operation. 
private void backgroundWorker1_RunWorkerCompleted(
    object sender, RunWorkerCompletedEventArgs e)
{
    // First, handle the case where an exception was thrown. 
    if (e.Error != null)
    {
        MessageBox.Show(e.Error.Message);
    }
    else if (e.Cancelled)
    {
        // Next, handle the case where the user canceled  
        // the operation. 
        // Note that due to a race condition in  
        // the DoWork event handler, the Cancelled 
        // flag may not have been set, even though 
        // CancelAsync was called.
        resultLabel.Text = "Canceled";
    }
    else
    {
        // Finally, handle the case where the operation  
        // succeeded.
        resultLabel.Text = e.Result.ToString();
    }

    // Enable the UpDown control. 
    this.numericUpDown1.Enabled = true;

    // Enable the Start button.
    startAsyncButton.Enabled = true;

    // Disable the Cancel button.
    cancelAsyncButton.Enabled = false;
}

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

.NET Framework

Supported in: 3.5, 3.0, 2.0

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