這是無效的，因爲它不存在於項目列表中的選定值

Question

我正在使用GridView並且在其中我有四列：labelID,fName,lName和Grade。 Grade是一個簡單的通過或失敗Radiobuttonlist。數據更新後，如果用戶通過或失敗，我希望它在下一次重新加載時提取數據以顯示選定的值。下面是代碼：

<asp:TemplateField> 
      <ItemTemplate> 
      <asp:RadioButtonList ID="rblChoices" runat="server" OnSelectedIndexChanged="rblChoices_SelectedIndexChanged" Text='<%# Eval("Grade") %>'> 
       <asp:ListItem Value="Pass" Text="Pass"></asp:ListItem> 
       <asp:ListItem Value="Fail" Text="Fail"></asp:ListItem> 
      </asp:RadioButtonList> 
      </ItemTemplate> 
</asp:TemplateField> 

C＃代碼：

protected void Page_Load(object sender, EventArgs e) 
{ 
    if (!Page.IsPostBack) 
    { 
     BindData(); 
    } 
} 
private void BindData() 
{ 
    string connectiongString = "Data Source=WSCJTCSQ1;Initial Catalog=LiquorStore;Integrated Security=True"; 
    SqlConnection myConnection = new SqlConnection(connectiongString); 
    SqlDataAdapter ad = new SqlDataAdapter("SELECT id, firstname, lastname, nickname, Grade FROM Company", myConnection); 
    DataSet ds = new DataSet(); 
    ad.Fill(ds); 
    gvUsers.DataSource = ds; 
    gvUsers.DataBind(); 
} 

預先感謝您！

Answer 1

您必須使用GridView的RowDataBound事件此

HTML

<asp:GridView runat="server" ID="gvUsers" OnRowDataBound="gvUsers_RowDataBound" AutoGenerateColumns="False"> 
    <Columns> 
     <asp:TemplateField> 
      <ItemTemplate> 
       <%# Eval("Name") %> 
      </ItemTemplate> 
     </asp:TemplateField> 
     <asp:TemplateField> 
      <ItemTemplate> 
       <asp:RadioButtonList ID="rblChoices" runat="server"> 
        <asp:ListItem Value="Pass" Text="Pass"></asp:ListItem> 
        <asp:ListItem Value="Fail" Text="Fail"></asp:ListItem> 
       </asp:RadioButtonList> 
      </ItemTemplate> 
     </asp:TemplateField> 
    </Columns> 
</asp:GridView> 

C＃代碼

一個非常簡單的公司類 - Company.cs

public class Company 
{ 
    public string Name { get; set; } 
    public string Grade { get; set; } 
} 

.aspx.cs

protected void Page_Load(object sender, EventArgs e) 
{ 

    List<Company> companies = new List<Company>() 
     { 
      new Company(){ Name = "Toyota", Grade = "Pass"}, 
      new Company(){ Name = "Form", Grade = "Fail"} 
     }; 

    gvUsers.DataSource = companies; 
    gvUsers.DataBind(); 
} 


protected void gvUsers_RowDataBound(object sender, GridViewRowEventArgs e) 
    { 
     if (e.Row.RowType == DataControlRowType.DataRow) 
     { 
      if (e.Row.DataItem != null) 
      { 
       string grade = DataBinder.Eval(e.Row.DataItem, "Grade") as string; 
       if (!string.IsNullOrEmpty(grade)) 
       { 
        RadioButtonList radio = e.Row.FindControl("rblChoices") as RadioButtonList; 
        radio.Items.FindByValue(grade).Selected = true; 
        //You can use this to select as well - see comments from Andomar 
        //radio.SelectedValue = grade; 
       } 
      } 
     } 
    } 

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