Delete data from DataGridView with confirmation using C# in Windows Forms Application

 iam using this code but it not working

private void dgvstudentreg_CellContentClick_1(object sender, DataGridViewCellEventArgs e)
{
    if (dgvstudentreg.CurrentCell.Value.ToString() == "Edit")
    {
        cs_field.Code = dgvstudentreg.SelectedRows[0].Cells[0].Value.ToString();
        txtRegno.Text = dgvstudentreg.CurrentRow.Cells["_regno"].Value.ToString();

        txtFName.Text = dgvstudentreg.CurrentRow.Cells["fname"].Value.ToString();
        txtMName.Text = dgvstudentreg.CurrentRow.Cells["mname"].Value.ToString();
        txtLName.Text = dgvstudentreg.CurrentRow.Cells["lname"].Value.ToString();
        txtBloodGrp.Text = dgvstudentreg.CurrentRow.Cells["Bloodgrp"].Value.ToString();
        txtHeight.Text = dgvstudentreg.CurrentRow.Cells["Height"].Value.ToString();
        txtWeight.Text = dgvstudentreg.CurrentRow.Cells["Weight"].Value.ToString();
        dtpBirthDate.Text = dgvstudentreg.CurrentRow.Cells["DateOfBirth"].Value.ToString();
        cmbGender.Text = dgvstudentreg.CurrentRow.Cells["Gender"].Value.ToString();
        txtCast.Text = dgvstudentreg.CurrentRow.Cells["Cast"].Value.ToString();
        pic_SPhoto.ImageLocation = dgvstudentreg.CurrentRow.Cells["Photo"].Value.ToString();
        txtCAddress.Text = dgvstudentreg.CurrentRow.Cells["CAddress"].Value.ToString();
        txtPAddress.Text = dgvstudentreg.CurrentRow.Cells["PAddress"].Value.ToString();
        txtMobileno1.Text = dgvstudentreg.CurrentRow.Cells["MobileNo1"].Value.ToString();
        //txtMobileno2.Text = dgvstudentreg.CurrentRow.Cells["MobileNo2"].Value.ToString();
        // txtEmailid.Text = dgvstudentreg.CurrentRow.Cells["EmailId"].Value.ToString();
        txtFatherfullname.Text = dgvstudentreg.CurrentRow.Cells["FatherName"].Value.ToString();
        txtFoccupation.Text = dgvstudentreg.CurrentRow.Cells["FatherOccupation"].Value.ToString();
        txtF_Mobileno.Text = dgvstudentreg.CurrentRow.Cells["FatherMobileno"].Value.ToString();
        //txtF_Officeno.Text = dgvstudentreg.CurrentRow.Cells["FatherOfficeno"].Value.ToString();
        txtMotherfullname.Text = dgvstudentreg.CurrentRow.Cells["MotherName"].Value.ToString();
        txtMoccupation.Text = dgvstudentreg.CurrentRow.Cells["MotherOccupation"].Value.ToString();
        txtM_Mobileno.Text = dgvstudentreg.CurrentRow.Cells["MotherMobileNo"].Value.ToString();
        //txtM_Officeno.Text = dgvstudentreg.CurrentRow.Cells["MotherOfficeNo"].Value.ToString();
        txtP_Schoolname.Text = dgvstudentreg.CurrentRow.Cells["PrvSchoolName"].Value.ToString();
        txtP_Durationform.Text = dgvstudentreg.CurrentRow.Cells["PrvDurationfor"].Value.ToString();
        txtP_Durationto.Text = dgvstudentreg.CurrentRow.Cells["PrvDurationto"].Value.ToString();
        txtP_Class.Text = dgvstudentreg.CurrentRow.Cells["PrvClass"].Value.ToString();
        //txtP_Marks.Text = dgvstudentreg.CurrentRow.Cells["PrvMarks"].Value.ToString();
        txtP_Contactno.Text = dgvstudentreg.CurrentRow.Cells["PrvSchoolcontno"].Value.ToString();


        btnSave.Text = "&Update";
        btnNew.Enabled = true;
        btnSave.Enabled = true;
    }
    if (dgvstudentreg.CurrentCell.Value.ToString() == "Delete")
    {
        if (DialogResult.Yes == MessageBox.Show("\tAre you sure to Delete this Student Details?\t\t", "Delete?", MessageBoxButtons.YesNo, MessageBoxIcon.Question))
        {
            //cs_field.Code1 = dgvstudentreg.CurrentRow.Cells["_regno"].Value.ToString();
            txtRegno.Text = dgvstudentreg.CurrentRow.Cells["_regno"].Value.ToString();
            cs_field.Code = txtRegno.Text;
            cs_studentreg.Deletestudent(cs_field);
            ClearField();
            MessageBox.Show("\t Student Details Deleted Successfully.\t\t", "Deleted", MessageBoxButtons.OK, MessageBoxIcon.Information);
            frmStudentRegistration_Load(this, EventArgs.Empty);
            btnSave.Text = "Save";
        }
    }
}