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VB.Net Int32.TryParse Conversion Exception

I understand this might be considered a duplicate of this: Parse v. TryParse

But, could anybody tell me why this code threw an exception when Tryparse is not supposed to throw any exceptions at all?

If Int32.TryParse(txtOrdLine.Text.Trim, txtOrdLine.Text) = False Then

The value entered in txtOrdLine was "1-4".

The exception was that it could not convert string "1-4" to type Integer. This is on a code behind for a ASP.Net 4.5 site if that makes a difference.

Any information would be appreciated.

Thanks.

Solution

  • The error is occurring because the automatic conversion the second parameter from String to Int32 is failing.

    VB.Net is effectively re-writing your code as:

    Dim temp as Int32
temp = Int32.Parse(txtOrdLine.Text) ' Exception here!
Int32.TryParse(txtOrdLine.Text.Trim, temp)
txtOrderLine.Text = temp.ToString()

    You'll need to create a temporary Int32 value and pass that into Int32.TryParse()