如何访问c＃中面板中的控件

Question

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'

Answer 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

1. PictureBox is followed by a period (.)
2. 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);

Answer 2

Try this:

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

Answer 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;
  }
}

Answer 4

Don't you want

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

instead of

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

Answer 5

在你的第二个块中，p.GetType == PictureBox之后的时间段是错误的（此处不需要句点）...就此而言，GetType是一个方法/函数而不是一个Property，所​​以它需要是p.GetType（）

Answer 6

你最好将图片框变成表单本身的私有变量，这样你就可以用它做事情，而不必每次都通过面板的控件。

Answer 7

I think

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

could be solution too.