How to stop code generator in designer in this case

Question

I am creating a custom control derived from ComboBox. I add some items to custom control in constructor of control.

// this code is sample
public MyCustomControl
{
this.Items.Add("test1");
this.Items.Add("test2");
}

When I drag this custom control to my form, designer auto-generate the code:

// this code in Form1.Designer.cs
this.mycustomControls.Items.AddRange(new object[] {
"test1",
"test2"});

When this custom control display on Form1, will have 4 items:
test1
test2
test1
test2

This problem cause duplication.

Please help me how to solve this problem, I don't want designer auto-generate these codes. Thanks.

Kirtan Patel · Answer

Hi Friend you can restrict duplication by Checking for existing items before adding it to combobox Code is Below For it dont forget to mark  Do you like answer  if answer helped you please it will give me some credits:) private void button2_Click( object sender EventArgs e) { //Check for Existence before Adding Items to ComboBox if ( comboBox1.Items.Contains(textBox1.Text) == false ) { // Add Item to Combo Box comboBox1.Items.Add(textBox1.Text.Trim()); } }