help creating an MRU menu

[flynn]

I am trying to create a generic class that will take a most-recently-used list and create a context menu for it. The code below (in a slightly different version) works perfect, but only if I have the function "BuildMRUSection()" in the CustomerClass. The reason for this is because the "tsmi.Click += " needs to be able to see the "OnMRURecentItemClick" event handler in order to assign it. What I need to be able to do is pass a pointer to the function "OnMRURecentItemClick" into the MRUList_Dynamic class in order to do the assignment within that class. This will make the routine more encapsulated and easier for the caller.

public partial class CustomerClass 
   {
MRUList_Dynamic mruDynamic = new MRUList_Dynamic();

       private void OnMouseDown(object sender, MouseEventArgs e)
       {
          if (e.Button == MouseButtons.Right)
   {
		MRUList_Dynamic mruDynamic = new MRUList_Dynamic();

		mruDynamic.BuildMRUSection(ref MRUMenuItem_Recent);  <-- need to be able to pass a function pointer here in order to wire up the mru menu items to the event

		((TextBox)sender).ContextMenuStrip = cmMRUList;
    }
}

// event handler for all mru menu items clicked
       private void OnMRURecentItemClick(object sender, EventArgs e)
       {
               ToolStripMenuItem tsmi = (ToolStripMenuItem)sender;

               if (tsmi.Equals(MRUMenuItem_Copy))
                   Clipboard.SetDataObject(tbxCustomerName.SelectedText);
               else if (tsmi.Equals(MRUMenuItem_Cut))
               {
                   Clipboard.SetDataObject(tbxCustomerName.SelectedText);
                   tbxCustomerName.SelectedText = "";
               }
               else if (tsmi.Equals(MRUMenuItem_Paste))
                   ;
               else if (tsmi.Equals(MRUMenuItem_Delete))
                   tbxCustomerName.SelectedText = "";
               else 
               {
				// set the textboxes based on the mru item selected
                   tbxCustomerName.Text = tsmi.Text;
                   tbxCustomerNumber.Text = tsmi.Tag.ToString();
               }
       }

  }


   public class MRUList_Dynamic
   {
       public const Int16 NUM_ITEMS = 10;
       const Byte NAME_COLUMN = 0;
       const Byte ID_COLUMN = 1;

// array contains the "most recently used" items
       static String[,] MRUArray = new String[NUM_ITEMS, 2] { { "", "" }, { "", "" }, { "", "" }, { "", "" }, { "", "" }, { "", "" }, { "", "" }, { "", "" }, { "", "" }, { "", "" } }; 

// adds the name/PCN pair in the first slot, moving all other items down 1 slot
       public static void AddName(String PCN, String sName)
       {
           for (Int16 x = NUM_ITEMS - 1; x > 0; x--)
           {
               MRUArray[x, ID_COLUMN] = MRUArray[x - 1, ID_COLUMN];
               MRUArray[x, NAME_COLUMN] = MRUArray[x - 1, NAME_COLUMN];
           }
           MRUArray[0, NAME_COLUMN] = sName;
           MRUArray[0, ID_COLUMN] = PCN;
       }

// retrieve the Name at a specific slot
       public static String GetNameAt(Int16 x)
       {
           return MRUArray[x, NAME_COLUMN];
       }

// retrieve the PCN at a specific slot
       public static String GetPcnAt(Int16 x)
       {
           return MRUArray[x, ID_COLUMN];
       }

// pass in the pop-up menu as a reference; then create the mru items
       public void BuildMRUSection(ref ToolStripMenuItem MRUMenuItem_Recent)
       {
           // if the dropdown menu items aren't cleared out, items might be duplicated over and over
           MRUMenuItem_Recent.DropDownItems.Clear();

           for (Int16 x = 0; x < NUM_ITEMS; x++)
           {
               ToolStripMenuItem tsmi =  new ToolStripMenuItem();
 
               if (tsmi.Text != "")
               {
                   tsmi.Size = new System.Drawing.Size(245, 22);
                   tsmi.Visible = true;
                   tsmi.Click += new EventHandler(OnMRURecentItemClick); //<--- need pointer to "OnMRURecentItemClick" function passed into here

                   MRUMenuItem_Recent.DropDownItems.Add(tsmi);

	}
    }
}
}

 

 

I've also tried to pre-fill (in the calling class) a ToolStripMenuItem's Click method with the address of the function of the event handler, then pass this into "BuildMRUSection()" as a template to create the mru menu items, but that doesn't work either.

 

   
// code to pass in a pre-filled "template" of the menu item
mruDynamic.BuildMRUSection(ref MRUMenuItem_Recent, tsmi_tmp);
       public void BuildMRUSection(ref ToolStripMenuItem MRUMenuItem_Recent, ToolStripMenuItem item_template)

[MrPaul]

Parameter type EventHandler

 

You could make the BuildMRUSection function take a parameter of type EventHandler, and then call it like so:

 

mruDynamic.BuildMRUSection(ref MRUMenuItem_Recent, new EventHandler(OnMRURecentItemClick));

 

Also, I don't see why MRUMenuItem_Recent needs to be ref, as you're not setting the value of it anywhere in the method.

 

Good luck :cool:

[flynn]

When I type "new" to create the code you suggested, "new" doesn't display in the drop-down that is displayed (this is the closest match: "NewsStyleUriParser").

 

Am I missing something?

[Nate Bross]

You want to use the new keyword, as in declaring a new object as opposed to the TYPE of object.

 

Did you try to copy/paste his code exactly?

[MrPaul]

EventHandler parameter

 

Your function would now become:

 

public void BuildMRUSection(ref ToolStripMenuItem MRUMenuItem_Recent, EventHandler clickHandler)
{
   //...
   tsmi.Click += clickHandler;
   //...
}

 

And called like so:

 

mruDynamic.BuildMRUSection(ref MRUMenuItem_Recent, new EventHandler(OnMRURecentItemClick));

 

Good luck :cool:

[flynn]

Got it to work. Thanks Nate for your reply. A special thank you to MrPaul, this is exactly what I needed.

 

MrPaul, I mis-read your original post and put the "new" in the definition instead of the method call, and of course the compiler was having none of that!