string validation

I would like to make sure the entered value in a text box on the windows form is as follows:
1)it must be seven characters long
2) it must comprise of the first character being a letter
3)and the following six characters being numerical digits.

Thanks

have you looked at using regular expressions. You could also use a validation control to assist this. See what you can find Im sure its the way to go.

Something like this?
Is a reg ex

VB Code:

[a-zA-Z]\w{1}\d{6}

Look although the reg ex doesnt work how it should this demonstrates me using the imports system.text.regularexpressions namespace then employing it in the validating event of my textbox control.
From here its just a case of getting the right regex.

VB Code:

Private Sub txtCallNotes_Validating(ByVal sender As Object, ByVal e As System.ComponentModel.CancelEventArgs) Handles txtCallNotes.Validating
        Dim expr As New Regex("\d{6}")
        If expr.ismatch(Me.txtCallNotes.Text) Then
            MessageBox.Show("OK")
        Else
            MessageBox.Show("Bad")
        End If
    End Sub

Use the Regex.IsMatch() function with FishGuy's regex string to compare the inputs.