HOWTO: Read Extender Properties from a UserControl

• Microsoft Visual Basic Learning, Professional, and Enterprise Editions for Windows, versions 5.0, 6.0

SUMMARY

There are times when your UserControl needs to check the value of an Extender Property when your control loads. This example shows how to check the values of Extender Properties from inside the UserControl. As an author of a control, you should not attempt to set Extender Properties with code in the UserControl.

MORE INFORMATION

Extender properties are provided by the container your control is placed on, but they appear to be a seamless extension of your control. A UserControl object can access extender properties through its Extender object.

To access an extender property, you must make sure your control is sited on the container. When the ReadProperties event of a UserControl happens, the control should be sited. However it still may not have access to all the extender properties. Because of this, the best place to read the value of an extender property is from the controls Show event.

Step-by-Step Example

1. Create a new ActiveX Control project. UserControl1 is created by default.



2. Change the BackColor of the UserControl to a different color such as red.



3. Add the following code to the UserControl:

   
         Private Sub UserControl_Show()
            Debug.Print "WhatsThisHelpID " & Extender.WhatsThisHelpID
   
            Debug.Print "Tooltiptext " & Extender.ToolTipText
            Debug.Print "HelpContextID " & Extender.HelpContextID
            Debug.Print "Tag " & Extender.Tag
            Debug.Print "Name " & Extender.Name
         End Sub
    




4. Close the UserControl's design and code windows.



5. From the File Menu, select Add Project, and add a Standard EXE project. Form1 is created by default.



6. Make the Standard EXE project the Startup project by choosing Properties from the Project menu and, on the General tab, pick Form1 as the Startup Object.



7. Place an instance of the UserControl on Form1. You will see a list of Extender properties in the Immediate Window.



8. Set the following properties for UserControl1 on Form1:

   
         WhatsThisHelpID = 101
         HelpContextID= 101
         Tag = "MyControl"
         ToolTipText = "Usercontrol"
         Name = "Bubba"
    




9. Save and run the project group. In the Immediate window you will see the new values for the different Extender properties.

REFERENCES

For more information, Search for Extender Object in Online Help and read "Understanding the Container's Extender Object" in the "Component Tools Guide."

Additional query words: kbDSupport kbDSD kbVBp kbVBp500 kbVBp600 kbCtrlCreate

Keywords : kbGrpVB
Version :
Platform : WINDOWS
Issue type : kbhowto