无法将控件放在Visual Studio中的表单上

Question

I'm a newbie with Visual Studio Express 2013 and C#. I've borrowed a simple C# Windows application which builds and runs fine, and now I want to add some objects to the main form.

I select an object from the Toolbox, then click in the Designer on my main form where I want it to appear. This works fine for some simple objects like Label, but when I select an OpenFileDialog object nothing appears on my form. An OpenFileDialog "box" appears in a bar below my form instead, and I can't drag it to my form (I get a slashed circle).

I'm surely missing something simple. Thanks for any help.

Answer 1

You cannot drag an OpenFileDialog to the form because it is a non visual control. To add an OpenFileDialog,just double click the control in the toolbox.That will add it to the form.Now to show the dialog you have to use OpenFileDialog.ShowDialog() in the code behind.Here is an example which shows the dialog on the click of a button.:

private void button1_Click(object sender, EventArgs e)
{
openFileDialog1.Filter = "Text Files (.txt)|*.txt|All Files (*.*)|*.*";
DialogResult result=  openFileDialog1.ShowDialog();
if(result==DialogResult.OK)
using (StreamReader reader = new StreamReader(openFileDialog1.FileName))
{
string s = reader.ReadLine();
}
}