C# 单击按钮后更改SQL数据网格视图

我正在尝试更改gridview中显示的SQL中的状态数据，但无法更改。我想在这里做的是，只要按下“批准”按钮，就可以将所选行的状态值更改为“A”。我可以知道怎么做吗

这是我的界面预览，下面是我的代码：

Aspx文件：

<%@ Page Title="" Language="C#" MasterPageFile="~/AdminTemplate.Master" AutoEventWireup="true" CodeBehind="ViewRequests.aspx.cs" Inherits="webAssignment_P05_Group2.ViewRequests" %>
<asp:Content ID="Content1" ContentPlaceHolderID="head" runat="server">
<style type="text/css">
    .auto-style2 {
        height: 388px;
        color: #000000;
        background-color: #FFFFFF;
    }
    .auto-style3 {
        width: 96%
    }
</style>
</asp:Content>
<asp:Content ID="Content2" ContentPlaceHolderID="ContentPlaceHolder1" runat="server">
<table class="auto-style3">
    <tr>
        <td class="auto-style2">
            <asp:GridView ID="gv_ParentRequests" runat="server" AllowPaging="True" AutoGenerateColumns="False" BackColor="White" BorderColor="#DEDFDE" BorderStyle="None" BorderWidth="1px" CellPadding="4" ForeColor="Black" GridLines="Vertical" Height="263px" Width="819px" AutoGenerateSelectButton="True" OnSelectedIndexChanged="gv_ParentRequests_SelectedIndexChanged" DataKeyNames="ViewingRequestID">
                <AlternatingRowStyle BackColor="White" />
                <Columns>
                    <asp:BoundField DataField="ViewingRequestID" HeaderText="Request ID" />
                    <asp:BoundField DataField="ParentName" HeaderText="ParentName" />
                    <asp:BoundField DataField="StudentName" HeaderText="StudentName" />
                    <asp:BoundField DataField="StudentID" HeaderText="StudentID" />
                    <asp:BoundField DataField="Status" HeaderText="Status" />
                    <asp:BoundField DataField="DateCreated" HeaderText="Date Created" />
                </Columns>
                <EmptyDataTemplate>
                    No record found!<br />
                </EmptyDataTemplate>
                <FooterStyle BackColor="#CCCC99" />
                <HeaderStyle BackColor="#6B696B" Font-Bold="True" ForeColor="White" />
                <PagerStyle BackColor="#F7F7DE" ForeColor="Black" HorizontalAlign="Right" />
                <RowStyle BackColor="#F7F7DE" />
                <SelectedRowStyle BackColor="#CE5D5A" Font-Bold="True" ForeColor="White" />
                <SortedAscendingCellStyle BackColor="#FBFBF2" />
                <SortedAscendingHeaderStyle BackColor="#848384" />
                <SortedDescendingCellStyle BackColor="#EAEAD3" />
                <SortedDescendingHeaderStyle BackColor="#575357" />
            </asp:GridView>
        &nbsp;</td>
    </tr>
    <tr>
        <td>
            <asp:Button ID="btn_ApproveViewRequest" runat="server" Text="Approve" Width="143px" OnClick="btn_ApproveViewRequest_Click" />
            <asp:Button ID="btn_RejectViewRequest" runat="server" Text="Reject" Width="143px" OnClick="btn_ApproveViewRequest_Click" />
        </td>
    </tr>
</table>
</asp:Content>

ParentRequest.cs：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Configuration;
using System.Data;
using System.Data.SqlClient;

namespace web_assignment_P05_group2
{
    public class ParentRequests
    {
        public int viewrequestid;
        public int parentid;
        public string studentname;
        public int studentid;
        public char status;
        public DateTime datecreated;

        public int ApproveReq(ref Dataset result)
        {
            string strConn = ConfigurationManager.ConnectionStrings
                             ["StudentEPortfolioConnectionString"].ToString();

            // Instantiate a SqlCOnnection object with the connection string read.
            SqlConnection conn = new SqlConnection(strConn);
            SqlCommand cmd = new SqlCommand("UPDATE ViewingRequest " +
        "SET Status = 'A' WHERE ViewingRequestID = @selectedViewingRequestID ", conn);

            SqlDataAdapter daRequest = new SqlDataAdapter(cmd);
            DataSet requests = new DataSet();

            conn.Open();
            daRequest.Fill(requests, "viewingRequest");
            conn.Close();

            return 0;
        }
    }
}

试试这个：

public int ApproveReq(ref Dataset result)
        {
            string strConn = ConfigurationManager.ConnectionStrings
                             ["StudentEPortfolioConnectionString"].ToString();

            // Instantiate a SqlCOnnection object with the connection string read.
            SqlConnection conn = new SqlConnection(strConn);
            SqlCommand cmd = new SqlCommand("UPDATE ViewingRequest " +
        "SET Status = 'A' WHERE ViewingRequestID = @selectedViewingRequestID ", conn);
cmd.parameters.add("@selectedViewingRequestID",Pass_selectedid);

            SqlDataAdapter daRequest = new SqlDataAdapter(cmd);
            DataSet requests = new DataSet();

            conn.Open();
            daRequest.Fill(requests, "viewingRequest");
            conn.Close();

            return 0;
        }

public int ApproveReq(ref Dataset result)
        {
            string strConn = ConfigurationManager.ConnectionStrings
                             ["StudentEPortfolioConnectionString"].ToString();

            // Instantiate a SqlCOnnection object with the connection string read.
            SqlConnection conn = new SqlConnection(strConn);
            SqlCommand cmd = new SqlCommand("UPDATE ViewingRequest " +
        "SET Status = 'A' WHERE ViewingRequestID = @selectedViewingRequestID ", conn);
cmd.parameters.add("@selectedViewingRequestID",Pass_selectedid);

            SqlDataAdapter daRequest = new SqlDataAdapter(cmd);
            DataSet requests = new DataSet();

            conn.Open();
            daRequest.Fill(requests, "viewingRequest");
            conn.Close();

            return 0;
        }