How to use validations for windows application with c#?

 private void btnFamilysaveandnext_Click(object sender, EventArgs e)
        {            
                txtAddress_Validated(this, e);
                txtcity_Validated(this, e);
                txtPincode_Validated(this, e);


                SqlConnection con = new SqlConnection(strConn);
                con.Open();
                SqlCommand cmd = new SqlCommand("sp_rm_insert_basicfamily", con);
                cmd.CommandType = CommandType.StoredProcedure;
                cmd.Parameters.AddWithValue("@FamilyID", txtFamilyid.Text);
                cmd.Parameters.AddWithValue("@HHID", txtHeadofhousehold.Text);
                cmd.Parameters.AddWithValue("@Religion", cbxReligion.SelectedValue);
                cmd.Parameters.AddWithValue("@Caste", cbxCaste.SelectedValue);
                cmd.Parameters.AddWithValue("@HouseNo", txtHouseno.Text);
                cmd.Parameters.AddWithValue("@Address1", txtAddress.Text);
                cmd.Parameters.AddWithValue("@Village", txtcity.Text);
                cmd.Parameters.AddWithValue("@State", cbxState.SelectedValue);
                cmd.Parameters.AddWithValue("@District", cbxDistrict.SelectedValue);
                cmd.Parameters.AddWithValue("@Mandal", cbxMandal.SelectedValue);
                cmd.Parameters.AddWithValue("@Pincode", txtPincode.Text);
                cmd.ExecuteNonQuery();
                con.Close();
                MessageBox.Show("Successfully Saved");
}

private void txtAddress_Validated(object sender, EventArgs e)
        {
            bool bTest = txtAddressValidate();
            if (bTest == true)
            {
                this.errorProvider1.SetError(txtAddress, "This field must contain text");
            }
            else
            {
                this.errorProvider1.SetError(txtAddress, "");
            }
        }
        private bool txtAddressValidate()
        {
            if (txtAddress.Text == string.Empty)
            {
                return true;
            }
            else
            {
                return false;
            }
        }

        private void txtcity_Validated(object sender, EventArgs e)
        {
            bool bTest = txtcityStringIsValid();
            if (bTest == true)
            {
                this.errorProvider1.SetError(txtcity, "Enter your City");
            }
            else
            {
                this.errorProvider1.SetError(txtcity, "");
            }
        }

        private bool txtcityStringIsValid()
        {
            if (txtcity.Text == string.Empty)
            {
                return true;
            }
            else
            {
                return false;
            }
        }

        private void txtPincode_Validated(object sender, EventArgs e)
        {
            bool bTest = txtPincodeStringIsValid();
            if (bTest == true)
            {
                this.errorProvider1.SetError(txtPincode, "Please enter 6 Digits");
            }
            else
            {
                this.errorProvider1.SetError(txtPincode, "");
            }
        }

        private bool txtPincodeStringIsValid()
        {
            char[] testArr = txtPincode.Text.ToCharArray();
            bool testBool = false;
            if (testArr.Length < 6)
            {
                testBool = true;
            }
            return testBool;
        }