private void button2_Click(object sender, EventArgs e) { string str = treeView1.SelectedNode.Text; int i = Convert.ToInt32(str.Length == 5 ? str.Substring(1, 1) : str.Substring(1, 2)); if (i == 1) { FrmStrengthCalculation1 childFrame = new FrmStrengthCalculation1(i); childFrame.Show(); } if (i == 2) { FrmStrengthCalculation2 childFrame = new FrmStrengthCalculation2(i); childFrame.Show(); } if (i == 3) { FrmStrengthCalculation2 childFrame = new FrmStrengthCalculation2(i); childFrame.Show(); } if (i == 4) { Form19 childFrame = new Form19(i); childFrame.Show(); } }