private void btnBack_Click(object sender, EventArgs e) { //display warning message DialogResult result = MessageBox.Show("If you click yes, you will lost all data.", "Make sure go back.", MessageBoxButtons.YesNo); //remove all data and go back to checklist if (result == DialogResult.Yes) { DataSheet.Columns.Clear(); CheckList.Visible = true; btnUpdate.Visible = true; menuData.Visible = false; layResult.Visible = false; lblAttedence.Visible = false; lblAttendence2.Visible = false; txtAttedence.Visible = false; resultAttendence.Visible = false; resultAttendence.Text = ""; emptyAttendence.Visible = false; lblInclass.Visible = false; lblInclass2.Visible = false; txtInclass.Visible = false; resultInclass.Visible = false; resultInclass.Text = ""; emptyInclass.Visible = false; lblAssignment.Visible = false; lblAssignment2.Visible = false; txtAssignment.Visible = false; resultAssignment.Visible = false; resultAssignment.Text = ""; emptyAssignment.Visible = false; lblMidterm.Visible = false; lblMidterm2.Visible = false; txtMidterm.Visible = false; resultMidterm.Visible = false; resultMidterm.Text = ""; emptyMidterm.Visible = false; lblFinal.Visible = false; lblFinal2.Visible = false; txtFinal.Visible = false; resultFinal.Visible = false; resultFinal.Text = ""; emptyFinal.Visible = false; lblOther.Visible = false; lblOthers2.Visible = false; txtOther.Visible = false; resultOther.Visible = false; resultOther.Text = ""; emptyOthers.Visible = false; lblInstruction.Visible = true; lblTotal.Visible = false; lblTotal.Text = ""; resultTotal.Visible = false; resultTotal.Text = ""; resultTotal2.Visible = false; resultTotal2.Text = ""; resultTotal3.Visible = false; resultTotal3.Text = ""; txtA.Text = ""; txtB.Text = ""; txtC.Text = ""; txtAttedence.Text = ""; txtInclass.Text = ""; txtAssignment.Text = ""; txtMidterm.Text = ""; txtFinal.Text = ""; txtOther.Text = ""; lblStatus.Text = "Choose category from list"; lblInstruction.Visible = true; foreach (int i in CheckList.CheckedIndices) { CheckList.SetItemCheckState(i, CheckState.Unchecked); } } }