当从下拉列表中选择项目时，如果gridview中不存在记录，则显示未找到的记录 [英] Display record not found, if recordsnot exists in gridview, when item selected from dropdownlist

问题描述

如果从下拉列表中选择项目时，如果gridview中不存在记录，则找不到显示记录

====================== ================================================== ==========================



嗨frnds，



正在使用asp.net c＃，sqlserver2005，


在我的网页上我有一个下拉列表和一个gridview。 4个文本框，用于从数据库中读取数据，并在gridview& ;;文本框根据下拉列表选择项目，



根据下拉列表，如果gridview中不存在记录。显示未找到的消息记录。



这是我的代码。

  protected   void  DDLStudents_SelectedIndexChanged（ object  sender ，EventArgs e）
 {
 
 SqlConnection conDisp =  new  SqlConnection（_connString）; 
 SqlCommand cmdDisp =  new  SqlCommand（）; 
 cmdDisp.Connection = conDisp; 
 
 cmdDisp.CommandText =  从Student_Records中选择*，其中Student_code =' + DDLStudents.SelectedValue +  '; 
 使用（conDisp）
 {
 conDisp.Open（）; 
 SqlDataReader readerDisp = cmdDisp.ExecuteReader（）; 
  if （readerDisp.Read（））
 {
 TxtPrincipal.Text = readerDisp [  Principal]。ToString（）; 
 TxtTeacher.Text = readerDisp [ 教师]。ToString（）; 
 TxtEmail.Text = readerDisp [  Email]。ToString（）; 
 TxtTelephone.Text = readerDisp [  TelephoneNo]。ToString（）; 
 
 GridBind（）; 
 
 
} 
 
 
 其他 
 {
 
 
 TxtPrincipal.Text =  ; 
 TxtTeacher.Text =  ; 
 TxtEmail.Text =  ; 
 TxtTelephone.Text =  ; 
} 
} 
 
 
} 
 
 
  public   void  GridBind（）
 {
 
 SqlConnection con =  new  SqlConnection （_connString）; 
 SqlCommand cmd =  new  SqlCommand（  select StudentName，RollNo，FathersName，Student_Records的标准，其中Student_code =' + DDLStudents.SelectedValue +  ' ，con）; 
 SqlDataAdapter Adpt =  new  SqlDataAdapter（cmd）; 
 DataTable dt =  new  DataTable（）; 
 Adpt.Fill（dt）; 
 lblCount.Text = dt.Rows.Count.ToString（）; 
 lblCount.Visible =  true ; 
 GVView.DataSource = dt; 
 GVView.DataBind（）; 
 
} 

在gridview中找不到记录时显示消息下拉列表。



注意：Pageloads时不会显示Gridview。根据下拉列表选择项目gridview将显示。



请提前帮助谢谢。

解决方案

尝试这个，



使用GridView的EmptyDataText属性。

 <   asp：GridView     EmptyDataText   = 找不到记录。    ID   =  grddata    runat   =  server >  
 <   / asp：GridView  >  

Display record not found, if records not exists in gridview, when item selected from dropdownlist
==================================================================================================

Hi frnds,

am working on asp.net c#, sqlserver2005,

on my webpage i have a dropdownlist and a gridview. and 4 textboxes to read the data from database am displaying data in gridview & textboxes according to dropdownlist selected item,

according to dropdownlist if records not exists in gridview. Display a message records not found.

This is my code.

protected void DDLStudents_SelectedIndexChanged(object sender, EventArgs e)
    {

        SqlConnection conDisp = new SqlConnection(_connString);
        SqlCommand cmdDisp = new SqlCommand();
        cmdDisp.Connection = conDisp;
      
        cmdDisp.CommandText = "Select * from Student_Records where Student_code ='" + DDLStudents.SelectedValue +"'";
        using (conDisp)
        {
            conDisp.Open();
            SqlDataReader readerDisp = cmdDisp.ExecuteReader();
            if (readerDisp.Read())
            {
                TxtPrincipal.Text = readerDisp["Principal"].ToString();
                TxtTeacher.Text = readerDisp["Teacher"].ToString();
                TxtEmail.Text = readerDisp["Email"].ToString();
                TxtTelephone.Text = readerDisp["TelephoneNo"].ToString();

                GridBind();


            }
            

            else
            {


                TxtPrincipal.Text = "";
                TxtTeacher.Text = "";
                TxtEmail.Text = "";
                TxtTelephone.Text = "";
            }
        }
       
        
        }
  
  
        public void GridBind()
    {
        
        SqlConnection con = new SqlConnection(_connString);
        SqlCommand cmd = new SqlCommand("select StudentName,RollNo, FathersName, Standard from Student_Records where Student_code = '" + DDLStudents.SelectedValue + "'", con);
        SqlDataAdapter Adpt = new SqlDataAdapter(cmd);
        DataTable dt = new DataTable();
        Adpt.Fill(dt);
        lblCount.Text = dt.Rows.Count.ToString();
        lblCount.Visible = true;
        GVView.DataSource = dt;
        GVView.DataBind();

    }

display a message when records not found in gridview according to dropdownlist.

Note: Gridview will not be displayed when Pageloads. Based on dropdownlist selected item gridview will be displayed.

Please help thanks in advance.

解决方案

Try this,

use EmptyDataText property of GridView.

<asp:GridView EmptyDataText="No Record Found." ID="grddata" runat="server">
    </asp:GridView>

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