Update UI using Parallel Task - multithreading

Question

I have method
public override void InitializeRow(object sender, InitializeRowEventArgs e)
{
if (!e.ReInitialize)
Task.Factory.StartNew(() =>
{
AfterInitializeRow(sender, e);
});
}
public override void AfterInitializeRow(object sender, InitializeRowEventArgs e)
{
foreach (UltraGridColumn ugc in e.Row.Band.Columns)
{
if (IsNumeric(ugc.Key))
{
e.Row.Cells[ugc].DroppedDown = true;
e.Row.Cells[ugc].ValueList = “Some value”;
e.Row.Cells[ugc].SetValue(e.Row.Cells[ugc.Key].Value, false);
e.Row.Cells[ugc].Style = Infragistics.Win.UltraWinGrid.ColumnStyle.DropDownList;
}
}
}
But its Giving error at e.Row.Cells[ugc].DroppedDown = true;
I learned that only Main thread can update the UI.
But is it possible that while updating the DroppedDown only it switch to main thread. Bcoz more than 1000’s rows are initialized in this way making the load of Grid very slow. So I want to do some kind of parallelism in this process.

Answer 1

In any function in your Form or UserControl, you can use the following type of code:
public void SetText(string text)
{
if (InvokeRequired)
{
BeginInvoke(new Action<string>(SetText), text);
}
else
{
label1.Text = text;
}
}
label1 would be the control to update in this case.
This will make sure that you invoke the function on the UI-thread.
You should still be careful with syncrhonization, though, but simply updating your UI from another thread can be easily done like that.

Answer 2

The answer to this question is that you shouldn't be using threading in the InitialzieRow event to set or even access properties on the grid or its related objects.
What you should do instead is look for ways to optimize what you are doing in this method first. For example why are you setting the value of a cell to the value it already has, this line of code should be able to be removed without impacting behavior.
Also all of the logic provided is only based on the column key so if the column has a consistent set of values, you could set the ValueList on the column in InitializeLayout instead of using InitializeRow.