Windows窗体：以模式方式打开另一个对话框窗口时，如何在文本框中保持焦点和光标

Question

I have a form frmFirst where I have a textBox for text entry. Then I want to open a second form (frmSecond) modally. This second form is like the form in WinWord "Insert Symbol" where a set of special symbols are accessible through button. The problem is that, when we are in the 2nd form and want to insert a symbol or character in the first one, we cannot see where the cursor is position within the text, because the focus came to frmSecond.

Any ideas to keep the cursor visually in the first form while pressing buttons on another one? Thanks

Answer 1

I don't think its possible to keep the cursor visually on the first form if you are using just the standard out of the box Textbox, but you can do the following:

Create a delegate to update the textbox on your first form:

public delegate void UpdateText(string s);

Which does the following:

private void UpdateText(string s)
{
    textBox1.Paste(s);
}

When you create your 2nd form, pass in the delegate, and call this as often as you like to insert at the correct location in the textbox:

UpdateText updDelegate = new UpdateText(UpdateText);
FormInput frmInput = new FormInput(updDelegate);
frmInput.Show(this);

Paste() will insert at the correct location, you could also keep track of the cursor position using the Leave/Click/KeyPress events and then when your 2nd form is closed give the focus back to the textbox in the correct position.