从数据库中检索数据到文本框

Question

The text of Label1 doesn't change, what could be the cause of this issue? Label1的文本没有改变，这个问题的原因可能是什么？

try
{
    string connectionString = @"Data Source = (localdb)\MSSQLLocalDB; Initial Catalog = db1; Integrated Security = True";
    SqlConnection cnn = new SqlConnection(connectionString);

    string query = "SELECT RNO FROM TABLE1 WHERE RNO='" + PRrno.Text + "'";

    SqlCommand cd = new SqlCommand(query, cnn);
    cnn.Open();

    SqlDataReader reader = cd.ExecuteReader();

    while (reader.Read())
    {
        Label1.Text = reader["RNO"].ToString();
    }

    reader.Close();
    cnn.Close();
}

Answer 1

Gaurav Thapa, like I said in one of the comments, make sure in the aspx file your elements have runat="server" also put all the elements you want to get refreshed inside an Ajax Update Panel Gaurav Thapa，就像我在其中一条评论中所说的那样，确保在 aspx 文件中您的元素具有 runat="server" 还将您想要刷新的所有元素放在 Ajax 更新面板中

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title>UpdatePanel</title>
</head>
<body>
    <form id="form1" runat="server">
        <asp:ScriptManager ID="ScriptManager1" runat="server" />
        <asp:UpdatePanel runat="server" id="UpdatePanel" updatemode="Always">        
            <ContentTemplate>
                <asp:Label runat="server" id="PRrno" />
            </ContentTemplate>
        </asp:UpdatePanel>       
    </form>
</body>
</html>

Answer 2

You have to get query output in data table and then from there convert that DataTable value to string.您必须在数据表中获取查询输出，然后从那里将该 DataTable 值转换为字符串。 Check if you have access to your label.检查您是否有权访问您的标签。

Label.Text = // String that you converted from DataTable Label.Text = // 从 DataTable 转换的字符串

从数据库中检索数据到文本框

问题描述

2 个解决方案

解决方案1
0 2020-02-13 05:18:51

解决方案2
-2 2020-02-12 03:03:55

从数据库中检索数据到文本框

问题描述

2 个解决方案

解决方案1 0 2020-02-13 05:18:51

解决方案2 -2 2020-02-12 03:03:55

解决方案1
0 2020-02-13 05:18:51

解决方案2
-2 2020-02-12 03:03:55