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xcorpionxting 0 Newbie Poster

I am working on a vb windows form application with several connected forms. Its used to manipulate a MySQL database. One of the sub-forms has the following code snippet:

1                myCommand.Connection = conn
2                myCommand.CommandText = SQL1
3                myAdapter.SelectCommand = myCommand
4                myAdapter.Fill(myData1)
5                ComboBox4.DataSource = myData1
6                ComboBox4.DisplayMember = "area_name"
7                ComboBox4.ValueMember = "area_name"

This works fine the first time I access the form, but if I go back to the main form then try to access the same sub-form again, I get a runtime error at line 4 saying "Argument NullException was undandled: Key cannot be null. Parameter name: key".

I tried disposing of myData1 (a data table) after use, but that still didn't work. Note that all the variables are declared as New in the beginning. Help?

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