未从数据列表的 findcontrol 获取文本框的正确值

Question

我正在尝试使用 Findcontrol 访问 DataList 中 label 和 textbox 的值。在运行程序中，我得到 label 的正确值，但没有来自 textbox 控件的值。这是代码

.aspx代码

<asp:DataList ID="SubjectAdded" runat="server">
    <ItemTemplate>
        <table>
            <tr>
                <td>
                    <asp:Label ID="SubjectLbl" runat="server" Text='<%# Eval("subject") %>'</asp:Label> 
                </td>
                <td>
                    <asp:TextBox ID="FeeBox" runat="server"></asp:TextBox>
                </td>
             </tr>
         </table>
     </ItemTemplate>
</asp:DataList>

.aspx.cs代码

 for(int i=0; i<SubjectAdded.Items.Count; i++)
        {
            string feeTB = ((TextBox)SubjectAdded.Items[i].FindControl("FeeBox")).Text;
            string subjectNameLb = ((Label)SubjectAdded.Items[i].FindControl("SubjectLbl")).Text ;

            string str = "UPDATE table name SET FEE='" + feeTB + "' WHERE TUTOR = '" + id+ "' AND SUBJECT = '" + subjectNameLb + "'";
            SqlCommand strCmd = new SqlCommand(str, con);
            con.Open();
            strCmd.ExecuteNonQuery();
            con.Close();
        }

Answer 1

这段代码对我有用，也许你错过了 IsPostback?:

protected void Page_Load(object sender, EventArgs e)
{
    if (!Page.IsPostBack)
    {
        SubjectAdded.DataSource = new[] {
            new {Id= 1, Subject = "Text 1"  },
            new {Id= 2, Subject = "Text 2"  },
        };
        SubjectAdded.DataBind();
    }
}

public void Page_PreRender(object sender, EventArgs e)
{
    for (int i = 0; i < SubjectAdded.Items.Count; i++)
    {
        string feeTB = ((TextBox)SubjectAdded.Items[i].FindControl("FeeBox")).Text;
        string subjectNameLb = ((Label)SubjectAdded.Items[i].FindControl("SubjectLbl")).Text;

        Response.Write($"{subjectNameLb}: {feeTB}<br/>");
    }
}

未从数据列表的 findcontrol 获取文本框的正确值

Not getting correct value of textbox from findcontrol from datalist

c#

asp.net

datalist

findcontrol