CODEWITHSUNDEEP
c#winformstype-conversion
Leron
Leron

Reputation: 9866

casting windows from control

I have this simple piece of code:

private void btnAdd_Click(object sender, EventArgs e)
{
    if (AskForSaveBeforeClose(null))
    {
        LoadForm<Soles>(btnAdd, "Add");
    }
}

btnAdd for now is my only button with ToolStripDropDown type. All other buttons are of ToolStripButton type. As you see I pass this button as e parameter to a method, and I use ToolStripButton as a parameter type in a lot other methods. I don't want to break my code too much, and I think it should be possible to cast btnAdd form ToolStripDropDownButton to ToolStripButton and solve my problem. Can this be done and if not do you have another idea to keep my code. I need the drop down functionality but any work-around is acceptable at the moment.

this is inheritance hierarchy : 

System.Object System.MarshalByRefObject 
System.ComponentModel.Component 
System.Windows.Forms.Control 
System.Windows.Forms.ScrollableControl 
System.Windows.Forms.ToolStrip 
System.Windows.Forms.MenuStrip 
System.Windows.Forms.StatusStrip 
System.Windows.Forms.ToolStripDropDown 
System.Windows.Forms.ToolStripDropDownMenu 
System.Windows.Forms.ContextMenuStrip

Upvotes: 4

Views: 1964

Answers (2)

Daniel A.A. Pelsmaeker
Daniel A.A. Pelsmaeker

Reputation: 50316

You cannot cast a ToolStripDropDownButton to a ToolStripButton as the former does not inherit from the latter. However, both inherit from ToolStripItem so you can cast to that instead.

Your say you do:

var button = ((btnSoles as ToolStripItem) as ToolStripButton);

However, this is not going to do what you want. First, btnSoles is always a ToolStripItem so you should use a direct cast instead:

var item = (ToolStripItem)btnSoles;

Then, if you really need functionality that is provided by ToolStripButton and not by ToolStripItem, only then should you use as:

var button = btnSoles as ToolStripButton;

This will return null if btnSoles cannot be cast to ToolStripButton. If it is a ToolStripDropDownButton, as you say, then it cannot be cast and the result will be null. Note that the double cast is not necessary, and rarely needed in general.

Upvotes: 2

Igor
Igor

Reputation: 15893

You will not be able to cast it unless ToolStripDropDownButton descends from ToolStripButton. If it does not, may be they have common ancestor that you can use as your parameter type.

Upvotes: 1

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