如何访问添加到面板的控件？

Question

I`m trying to modify on job the Text of a label (label.Text) that I have previously added to a panel (MyPanel.Controls.Add(MyLabel).

I add the label to the panel in a function:

public PanelEx nameoffunction()
{
.
.
MyPanel.Controls.Add(MyLabel);
return MyPanel;
.
.
}
MyPanelWithControl = nameoffunction();

Now I have in MyPanelWithControl the panel with a label. How can I now access to the label previously added to modify one of its fields?

Answer 1

You can find a control using its Name property:

MyLabel.Name = "label1";
MyPanel.Controls.Add(MyLabel);
...
MyPanel.Controls["label1"].Text = "updated text";

However, this approach can lead to problems later if you make changes to your user interface. If you moved the label to another panel, or changed its name, then the code which tries to find it using the name would still compile but cause an error at runtime. For long-term projects it's preferable to store references to controls as properties:

public class PanelEx : Panel {
    ...
    public Label MyLabel { get; set; }
}

public PanelEx nameoffunction() {
    ...
    MyPanel.MyLabel = MyLabel;
    return MyPanel;
}

And then you can access the Label directly from the panel object:

MyPanel.MyLabel.Text = "updated text";