Question

Error : specific argument was out of range of valid value parameter name : index

This error message occurred every 2min in design time!!

what should i do?

Answer 1

The designer executes code from controls on the design surface at design time. This error is probably coming from code in one of your UserControls, or possibly a buggy third party control.

Things you can do to help prevent code being executed at Design Time:

• Avoid putting such code in the constructor of your UserControl.

• Use if (this.DesignMode) to conditionally suppress the code at design-time. It’s common to do this in the OnLoad method.

• Mark properties in your usercontrol that should not be evaluated at design-time with appropriate attributes, e.g.:

  [
  Browsable(false),
  DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)
  ]
  public MyType MyRuntimeOnlyProperty
  {
      ...
  }
  

If all else fails, you can start a second instance of Visual Studio, and attach its debugger to your instance that’s running the Designer. Then break on the appropriate exception.