CODEWITHSUNDEEP
.netvb.netcolorssubroutinebackcolor
jacob Denis
jacob Denis

Reputation: 51

Cannot change the back color of a button via a custom method

Here is my code that should change the back color of any of my buttons, but it doesn't work and I don't have any idea what's wrong:

Public Sub color(ByVal backcolor As System.Drawing.Color)
    backcolor = Drawing.Color.CadetBlue
End Sub

And here is how I call it when a button was clicked. It should change the back color of Button1, but it doesn't. Am I doing it right or am I missing something?

Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
    color(Button1.BackColor)
End Sub

Upvotes: 1

Views: 444

Answers (3)

Matt Wilko
Matt Wilko

Reputation: 27342

You could create an extension method to do this. Create a public module as follows:

Public Module Module1    
    <Runtime.CompilerServices.Extension()>
    Public Sub SetBackColourToCadetBlue(aButton As Button)
    'Use the following line for Telerik Button
    'Public Sub SetBackColourToCadetBlue(aButton As Telerik.WinControls.UI.RadButton) 
        aButton.BackColor = Color.CadetBlue
    End Sub
End Module

The you can just call the following to set the backcolor of any button:

Button1.SetBackColourToCadetBlue()

Upvotes: 1

BanForFun
BanForFun

Reputation: 752

Public Sub color(ByVal btn As Control, ByVal clr As System.Drawing.Color)
    btn.BackColor = clr
End Sub

Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
    color(Button1, Drawing.Color.CadetBlue)
End Sub

Or

Public Sub color(ByVal btn As Control)
    btn.BackColor = Drawing.Color.CadetBlue
End Sub

Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
    color(Button1)
End Sub

That works with any control (Textboxes, Labels e.t.c)

Upvotes: 1

Chris Dunaway
Chris Dunaway

Reputation: 11216

System.Drawing.Color is a value type (structure). When you pass it to your color method, only a copy is passed and your method only changes the copy. You should change your Sub to a Function and return the color and assign it to the button's BackColor property:

Public Function color() As System.Drawing.Color
    Return System.Drawing.Color.CadetBlue
End Function

Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
    Button1.BackColor = color()
End Sub

Although that function doesn't add any value. You should probably just set the color directly:

Button1.BackColor = System.Drawing.Color.CadetBlue

Per @VisualVincent's comment, you can use ByRef in your Sub:

Private Sub ChangeColor(ByRef c As System.Drawing.Color)
    c = Color.CadetBlue
End Sub

Upvotes: 1

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