如何在一个循环中按字符串访问拖放按钮？

Question

I am working on a desktop application which includes graphic scheme and that scheme has 50 drag-and-drop buttons(they are not dynamically allocated) they are all named similar(for example button 1 is btnP1, button 2 is btnP2 etc...). I would like to access those buttons with a for loop using string, I checked some previous posts on this site but none of those answers helped my problem.

I wrote 50 lines of codes to add those buttons to controls, and the same moment I add them to the controls they disappear from the graphic scheme. Later I tried to access them through for loop, but nothing happened, since they disappear once I add them to the controls..

        this.Controls.Add(btnP1);
        this.Controls.Add(btnP2);
        this.Controls.Add(btnP3);
        this.Controls.Add(btnP4);
        ... and so on
        this.Controls.Add(btnP47);
        this.Controls.Add(btnP48);
        this.Controls.Add(btnP49);
        this.Controls.Add(btnP50);

for(int i = 1; i <= 50; i++)
{
this.Controls["btnP"+ i.ToString()].Visible= False;
}

I would like to find out if there is some other way to access my buttons, because I need them to be shown and hidden.

Answer 1

To loop over all buttons within one control you can use a foreach loop

foreach(Button btn in this.Controls.OfType<Button>())
{
   btn.Visible = false; //every button in you Control
}

With this code lines you run through the entire Control .

With the OfType method you filter only the buttons out of the control. So you prevent an InvalidCastException error.

Enumerable.OfType

Answer 2

Similar to Mario's answer but I would probably expand the selectors if their naming is consistent and filter out ones that can't be dropped:

        foreach (Button btn in this.Controls.OfType<Button>().Where(x => x.Name.StartsWith("btnP") && x.AllowDrop))
        {
            btn.Visible = false;
        }

Answer 3

LINQ version:

this.Controls
.OfType<Button>()
.Where(b => b.Name.StartsWith("btnP") && b.AllowDrop)
.ToList()
.ForEach(b => b.Visible = false);