Creating Generic Method to Create Controls in ASP.NET C#

Question

I am trying to generate a method on a custom control that will take an object I have created with metadata pertaining to the control and have the control created in this one method and added to the page control collection. Below is the object that I created to contain the control metadata.

public class ListControlSetup
{
    public ListControl ListControl { get; set; }
    public String ControlId { get; set; }
    public String ControlCssClass { get; set; }
    public bool CausesValidation { get; set; }
    public IuIDropDownDictionary DropDownDictionary { get; set; }
    public String DropDownMethod { get; set; }
    public bool AutoPostback { get; set; }                      
}

I then have a method that takes the above object as a parameter and creates the control. Lets say a dropdownlist in this instance. Lets say I wanted to pass an Event for the dropdownlist OnSelectedIndexchange event. How would I do this in a generic fashion so that I could have the event wired up in the called procedure. Below is the called procedure I currently have.

    private void ControlSetUp(ListControlSetup control)
    {
        control.ListControl = this.CreateDropDownListControl(control.ControlId, control.ControlCssClass, control.CausesValidation);
        _myManager.DropDownMethod = control.DropDownMethod;
        _myManager.FillDropDown(control.DropDownDictionary, control.ListControl);                       
        this.Controls.Add(control.ListControl);
    }

below is the call and object instantiation.

        ListControlSetup lcs = new ListControlSetup{ ListControl = ddlControl, DropDownMethod = SPConsts.GetData, 
                            DropDownDictionary = new DataDictionary(), ControlId="ddlControlId", ControlCssClass="inputfield", CausesValidation=false, AutoPostback=false};
        ControlSetUp(lcs);        

Any advice would be great as to how I would add events to the ControlSetUp method.

Thank You

Answer 1

The solution to your problem is with delegates. The DropDownList.OnSelectedIndexChanged event is declared using a delegate of type EventHandler (which itself is declared in System.dll). So add a method of the same EventHandler type to your ListControlSetup class, like this:

public class ListControlSetup
{
    ...
    EventHandler OnSelectedIndexChanged;  
    // Don't let the stackoverflow coloring fool you, 
    // 'OnSelectedIndexChanged' is a member variable name.
}

Then, in your ControlSetUp() method, do this:

if ( control.OnSelectedIndexChanged != null )
    ddlControl.SelectedIndexChanged += control.OnSelectedIndexChanged;

Finally, to assign the ListControlSetup's OnSelectedIndexChanged list member, do this:

ListControlSetup lcs = new ListControlSetup() { ... };
lcs.OnSelectedIndexChanged += new EventHandler( ddl_SelectedIndexChanged );

That assumes your event handler method is ddl_SelectedIndexChanged, of course.

Hope this helps!