Override User Control Component

Here is one way to Overwrite a UserControl.

public class ControlName: DropDownList / Image / button / .......

{

     protected override void OnInit(EventArgs e)

     {

        if (!DesignMode){       ........................   }

        base.OnInit(e).

     }

}

web.config for imagrate the Class Library Project into website. 

    <pages validateRequest="false" enableEventValidation="false" viewStateEncryptionMode="Never" enableViewStateMac="false" styleSheetTheme="Theme1">
      <namespaces>
        <add namespace="**************"/>
      </namespaces>
      <controls>        <add tagPrefix="****" namespace="*********" assembly="********"/>      </controls>
      <tagMapping>
      </tagMapping>
    </pages>