How to Validate ComboBox

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Hi friends

I have written a function that validates comboboxes in my project. The function works fine with comboboxes that are populated at design time. But it will not work when I used it with comboboxes that via database at runtime

I have show the function and the validate event handler for comboboxes

The function:

VB

 Public Function validateCombo(txt As ComboBox) As Boolean
 If Not txt.Items.Contains(txt.Text.ToString) Then
    Return False
 Else
    Return True
 End If
End Function

Combo event handler:

VB

Private Sub cboFund_Validating(sender As Object, e As System.ComponentModel.CancelEventArgs) Handles cboFund.Validating
       If Not bnformclosing Then
           If cboFund.Text <> String.Empty Then

               If validateCombo(cboFund) Then
                   e.Cancel = False
               Else
                   MessageBox.Show("The item: " & cboFund.Text & " is not a valid fund", "Invalid fund", MessageBoxButtons.OK, MessageBoxIcon.Information)
                   e.Cancel = True
               End If
           End If
       End If
   End Sub

Posted 17-Dec-12 7:05am

noblepaulaziz

Updated 17-Dec-12 7:08am

__TR__

v2

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Comments

Kschuler 17-Dec-12 13:43pm

What error message do you get? What do you mean by "it will not work"?

noblepaulaziz 17-Dec-12 15:26pm

it does not pass validation test. Which means that the item is not in the list whereas the item is in the list

Kschuler 17-Dec-12 16:24pm

Perhaps instead of checking the Text of the combobox, you should check the SelectedValue?

noblepaulaziz 17-Dec-12 16:57pm

Thanks for the reply. I will try your suggestion and let you know the feedback

Thanks once again

Sergey Alexandrovich Kryukov 17-Dec-12 14:28pm

Bad idea: you are showing modal MessageBox each time you are validating. Use something non-modal, just output some validation results in some control on the same form.
—SA

2 solutions

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This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Akbar Ali Hussain · Answer 1 · 2012-12-17T12:53:00

ComboBox.Items.Contains() method search through the object collection which are bound to the ComboBox. When you add string values, this method can be called by providing a string value as parameter. But when you bind a DataTable, the object type will be DaraRow. You have to provide a DataRow object to ComboBox.Items.Contains() method in this scenario.

Or use ComboBox.FindString() or ComboBox.FindStringExact(). That is the easiest way

ankur789 · Answer 2 · 2012-12-17T21:13:00

Solution 4

You Can use the Combobox dropdown list property

Posted 17-Dec-12 21:13pm

ankur789

How to Validate ComboBox

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How to Validate ComboBox

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