How to access controls that is in the panel in c#

问题

I use a panel in c# winforms and fill the panel with the no of picture box using loop

For example, panel name is panal

foreach (string s in fileNames)
{            
    PictureBox pbox = new new PictureBox();
    pBox.Image = Image.FromFile(s);
    pbox.Location = new point(10,15);
    .
    .
    .
    .
    this.panal.Controls.Add(pBox);
}

now I want to change the location of picturebox in another method. The problem is that how can now I access the pictureboxes so that I change the location of them. I try to use the following but it is not the success.

foreach (Control p in panal.Controls)
                if (p.GetType == PictureBox)
                   p.Location.X = 50;

But there is an error. The error is:

System.Windows.Forms.PictureBox' is a 'type' but is used like a 'variable'

回答1:

There appear to be some typos in this section (and possibly a real error).

foreach (Control p in panal.Controls)
                if (p.GetType == PictureBox.)
                   p.Location.X = 50;

The typos are

PictureBox is followed by a period (.)
GetType is missing the parens (so it isn't called).

The error is:

You can't compare the type of p to PictureBox, you need to compare it to the type of PictureBox.

This should be:

foreach (Control p in panal.Controls)
   if (p.GetType() == typeof(PictureBox))
      p.Location = new Point(50, p.Location.Y);

Or simply:

foreach (Control p in panal.Controls)
   if (p is PictureBox)
      p.Location = new Point(50, p.Location.Y);

回答2:

Try this:

foreach (Control p in panal.Controls)
{
    if (p is PictureBox)
    {
        p.Left = 50;
    }
}

回答3:

Next there might be some bugs in your for loop.

foreach (Control p in panel.Controls)
{
  if (p is PictureBox) // Use the keyword is to see if P is type of Picturebox
  {
     p.Location.X = 50;
  }
}

回答4:

I think

foreach (PictureBox p in panel.Controls.OfType<PictureBox>())
        {
            p.Location = new Point(50, p.Location.Y);
        }

could be solution too.

回答5:

Don't you want

panel.Controls
 //^ this is an 'e'

instead of

panal.Controls?
 //^ this is an 'a'

回答6:

In your second block the period after p.GetType == PictureBox is wrong (no period required here)... for that matter, GetType is a method/function not a Property so it needs to be p.GetType()

回答7:

You would be better off making the picturebox a private variable of the form itself, so that you could do things with it without having to step though the panel's controls every time.

来源：https://stackoverflow.com/questions/1260296/how-to-access-controls-that-is-in-the-panel-in-c-sharp

标签

winforms

desktop-application