CODEWITHSUNDEEP
c#.netwinformscomboboxcontrols
MBU
MBU

Reputation: 5098

Can I disable a combobox in WinForms without graying it out?

Is there a way to disable value change for a combo box without graying it out in windows forms? I saw a few posts but they were for WPF and didnt help my situation.

Upvotes: 6

Views: 5723

Answers (5)

Oliver Hanau
Oliver Hanau

Reputation: 11

Setting the focus to the next control in the Enter handler, makes the ComboBox entirely resistant to clicks and is exactly what I needed.

The comboBox1.DropDownHeight = 1; in the accepted answer shows a weird one-pixel dropdown that looks kinda broken to my UI-sensitive eyes.

The only disadvantage I've found is that one can't Shift-Tab across the field but in my case that's not a problem.

Upvotes: 1

Hans Passant
Hans Passant

Reputation: 941277

Nah, not good enough. Make it disabled and look exactly like the original so the user is completely fooled. Add a new class and paste this code.

using System;
using System.Drawing;
using System.Windows.Forms;

class FakeComboBox : ComboBox {
    private PictureBox fake;
    public new bool Enabled {
        get { return base.Enabled; }
        set { if (!this.DesignMode) displayFake(value);
              base.Enabled = value;
        }
    }
    private void displayFake(bool enabled) {
        if (!enabled) {
            fake = new PictureBox();
            fake.Location = this.Location;
            fake.Size = this.Size;
            var bmp = new Bitmap(fake.Size.Width, fake.Size.Height);
            this.DrawToBitmap(bmp, new Rectangle(0, 0, bmp.Width, bmp.Height));
            fake.Image = bmp;
            this.Parent.Controls.Add(fake);
            fake.BringToFront();
            fake.Click += delegate { Console.Beep(); };
        }
        else {
            this.Parent.Controls.Remove(fake);
            fake.Dispose();
            fake = null;
        }
    }
}

The very slight 'glow' you get on Win7 when you re-enable it is very interesting.

Upvotes: 0

Fantius
Fantius

Reputation: 3862

In the GotFocus hander (whatever it is called), set the focus to something else.

Upvotes: 0

Chuck Savage
Chuck Savage

Reputation: 11945

Then save his handlers as variables and simply -= them after.

Example:

var keyDown = (s, e) => e.Handled = true;
var keyPress = (s, e) => e.Handled = true;
var keyUp = (s, e) => e.Handled = true;

Then replace in his with:

comboBox1.KeyDown += keyDown;
comboBox1.KeyPress += keyPress;
comboBox1.KeyUp += keyUp;

Then when you want to remove:

comboBox1.KeyDown -= keyDown;
comboBox1.KeyPress -= keyPress;
comboBox1.KeyUp -= keyUp;

Upvotes: 0

Sanjeevakumar Hiremath
Sanjeevakumar Hiremath

Reputation: 11263

Setting these on your comobobox will do the trick you are looking for, Combo is enabled but nobody can change or type anything so Appearance = Enabled, Behaviour = Disabled :)

        comboBox1.DropDownHeight = 1;
        comboBox1.KeyDown += (s, e) => e.Handled = true;
        comboBox1.KeyPress += (s, e) => e.Handled = true;
        comboBox1.KeyUp += (s, e) => e.Handled = true;

If for some reason you cannot use lambdas then following handlers can be associated. Right Click -> Paste has to be handled additionally if you have DropDownStyle = DropDown.

    //void comboBox1_KeyUp(object sender, KeyEventArgs e)
    //{
    //    e.Handled = true;
    //}

    //void comboBox1_KeyPress(object sender, KeyPressEventArgs e)
    //{
    //    e.Handled = true;
    //}

    //void comboBox1_KeyDown(object sender, KeyEventArgs e)
    //{
    //    e.Handled = true;
    //}

Upvotes: 6

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