How to manipulate a Windows Forms control from another thread and get return value via Invoke() method


I was working on a Windows Forms project and I had this requirement to basically do some manipulation on a TreeListView on the parent form (MainForm in this case) for which we already had a developed a method and also to get the return value back from it. To make life even easier, we needed to do this from a BackGroundWorker thread in this case. Now, the problem with Windows Forms controls is that they can’t be manipulated apart from the main thread, so I had to look for a work around of some sort. So here’s a little modified snippet of the code for your understanding:-

if (m.treeListView.InvokeRequired)
{
ra= (ReportData?)m.treeListView.Invoke(new Func<ReportData?>(
() => m.CreateDataforReport(“Rpt type”, false)));
//m is the main form’s reference!

}

So what I’ve done is that I passed the main form’s reference to the child form in the constructor and made the TreeListView and the CreateDataforReport public. Notice that I called CreateDataforReport method inside the Func<ReportData?> and not directly. This is what enables you to get the appropriate return value, be it string, integer or any complex type like I have it here.

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Author: Imran Akram

A .NET/SharePoint Consultant and a political enthusiast who believes in putting the feet of the elected and/or unelected officials to fire in order to get good governance.

2 thoughts on “How to manipulate a Windows Forms control from another thread and get return value via Invoke() method”

  1. An outstanding share! I’ve just forwarded this onto a colleague who had been doing a little research on this.
    And he actually bought me lunch because I found it for him…
    lol. So let me reword this…. Thank YOU for the meal!!
    But yeah, thanks for spending the time to
    talk about this issue here on your web site.

  2. My brother suggested I may like this website. He was once totally right.
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