CODEWITHSUNDEEP
.netvb.netwinforms
Wine Too
Wine Too

Reputation: 4655

Winforms Combobox selects text on Forms fontchange

I have never noted strange behaviour on Comboboxes until now. For see what is happening you may create a minimal example. Open a new project, put textbox, two comboboxes with DropDownStyle=DropDown (what is initial) and button on it and paste following code to Form.

Public Class Form1
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles Me.Load

    TextBox1.Text = "Mess"
    Button1.Text = "Increase Font"
    ComboBox1.Items.AddRange({"One", "Two", "Three"})
    ComboBox1.Text = "Two"
    ComboBox2.Items.AddRange({"Left", "Right", "Up", "Down"})
    ComboBox2.Text = "Up"
End Sub

Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click

    Me.Font = New Font(Me.Font.Name, Me.Font.Size + 1)
    TextBox1.Focus()
End Sub
End Class

What is happenning is that in case of pressing a Button1 Form's fontsize increases and Comboboxes selects his text! That way my GUI becames messed.

Did anybody know how to get rid of that and get Comboboxes with expected functionality?

Upvotes: 2

Views: 76

Answers (1)

T.S.
T.S.

Reputation: 19340

It seem to be some problem in framework. Consider it "funny behavior". But you can do this

Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click

    Me.Font = New Font(Me.Font.Name, Me.Font.Size + 1)
    TextBox1.Focus()
    ComboBox1.SelectionLength = 0
    ComboBox2.SelectionLength = 0

End Sub

If your cbo is sub-classed as you pointed in the comment than in your super class add

Private Sub ComboBox2_Layout(sender As Object, e As LayoutEventArgs) Handles ComboBox2.Layout
    DirectCast(sender, ComboBox).SelectionLength = 0
End Sub

this works for all cbo's on the form

Private Sub Form1_Layout(sender As Object, e As LayoutEventArgs) Handles MyBase.Layout
    For Each c As Control In Me.Controls
        Dim combo As ComboBox = TryCast(c, ComboBox)
        If combo IsNot Nothing AndAlso combo.DropDownStyle = ComboBoxStyle.DropDown Then
            combo.SelectionLength = 0
        End If
   Next
End Sub

Upvotes: 2

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