how set keypress in form in c#

Do the following:

Set the form's KeyPreview to true so that the form can capture the Spacebar.

this.KeyPreview = true;

Then use the KeyDown event of the form:

this.KeyDown += new KeyEventHandler(Form1_KeyDown);

Suppose you have a button's event handler like this:

private void button1_Click(object sender, EventArgs e)
        {
            MessageBox.Show("Button clicked");
        }

Use the button1.PerformClick() in the Form1_KeyDown function:

void Form1_KeyDown(object sender, KeyEventArgs e)
        {
            if (e.KeyCode == Keys.Space)
            {
                button1.PerformClick();  // This will call the button1_Click event handler
            }
        }

Should work now.