Parameter count mismatch with Invoke?

问题:

The code block below results in the error: TargetParameterCountException was unhandled by user code. Parameter count mismatch.

    public void AddListViewItem(string[] Data)
    {
        if (InvokeRequired)
        {
            Invoke(new Action<string[]>(AddListViewItem), Data);
        }
        else
        {
            ListViewData.Items.Add(Data[0]).SubItems.AddRange
            (
                new string[]
                { 
                    Data[1],
                    Data[2],
                    Data[3],
                }
            );
        }
    }

Any ideas?

回答1:

The error occurs because of array covariance; an array of strings is assignable to object[]. This causes the Invoke method to treat each element of the string array as if it should be an argument to the AddListViewItem method.

Here's a fix:

Invoke(new Action<string[]>(AddListViewItem), new object[] {Data});

(or)

Invoke(new Action<string[]>(AddListViewItem), (object)Data);

This makes it crystal-clear to Invoke that the target method takes a single parameter.

回答2:

UPDATE information:

If you are using Windows Server 2008 R2, take a look at Windows Update for .Net Framework 4.5.1 for Windows Server 2008 R2 x64 based systems KB2858725. For me, after installed this update fixed this issue.