ASP.NET GridView中如何检测DropDownList选项是否被修改

方法1：利用已添加的HiddenField获取初始值 #

你已经在EditItemTemplate中添加了HiddenField1存储初始的MemberApproved值，直接在RowUpdating事件中获取该控件的值即可完成对比：

protected void GridView1_RowUpdating(object sender, GridViewUpdateEventArgs e)
{
    DropDownList ddl = (DropDownList)GridView1.Rows[e.RowIndex].FindControl("ddlStatus");
    string NewSelection = ddl.SelectedValue;
    
    // 获取初始值
    HiddenField hiddenInitial = (HiddenField)GridView1.Rows[e.RowIndex].FindControl("HiddenField1");
    string InitialSelection = hiddenInitial.Value;
    
    // 判断是否修改
    if (NewSelection != InitialSelection)
    {
        // 执行值修改后的业务逻辑
    }
}

方法2：通过GridView的DataKeys获取初始值 #

借助GridView的DataKeys存储初始值，无需额外添加HiddenField：

1. 修改GridView的DataKeyNames属性，加入MemberApproved：

<asp:GridView ID="GridView1" runat="server" ... DataKeyNames="Id,MemberApproved" ...>

2. 在RowUpdating事件中直接从DataKeys读取初始值：

protected void GridView1_RowUpdating(object sender, GridViewUpdateEventArgs e)
{
    DropDownList ddl = (DropDownList)GridView1.Rows[e.RowIndex].FindControl("ddlStatus");
    string NewSelection = ddl.SelectedValue;
    
    // 从DataKeys获取初始值
    string InitialSelection = GridView1.DataKeys[e.RowIndex]["MemberApproved"].ToString();
    
    // 对比判断
    if (NewSelection != InitialSelection)
    {
        // 处理修改逻辑
    }
}

方法3：在RowEditing事件中缓存初始值 #

在用户触发编辑操作时，将初始值存入ViewState，后续在RowUpdating中取出对比：

1. 添加RowEditing事件处理：

protected void GridView1_RowEditing(object sender, GridViewEditEventArgs e)
{
    // 获取当前行的初始状态值
    Label lblStatus = (Label)GridView1.Rows[e.NewEditIndex].FindControl("Label1");
    string initialValue = lblStatus.Text;
    
    // 用行Id作为标识存入ViewState，避免多编辑行冲突
    int rowId = Convert.ToInt32(GridView1.DataKeys[e.NewEditIndex]["Id"]);
    ViewState["InitialStatus_" + rowId] = initialValue;
    
    // 进入编辑模式
    GridView1.EditIndex = e.NewEditIndex;
    GridView1.DataBind();
}

2. 在RowUpdating事件中取出缓存值并对比：

protected void GridView1_RowUpdating(object sender, GridViewUpdateEventArgs e)
{
    DropDownList ddl = (DropDownList)GridView1.Rows[e.RowIndex].FindControl("ddlStatus");
    string NewSelection = ddl.SelectedValue;
    
    // 获取当前行Id并取出缓存的初始值
    int rowId = Convert.ToInt32(GridView1.DataKeys[e.RowIndex]["Id"]);
    string InitialSelection = ViewState["InitialStatus_" + rowId]?.ToString();
    
    if (InitialSelection != null && NewSelection != InitialSelection)
    {
        // 执行修改后的逻辑
    }
    
    // 清理ViewState中的缓存数据
    ViewState.Remove("InitialStatus_" + rowId);
}

内容的提问来源于stack exchange，提问作者AM_MA