如何在下拉列表中检索值 [英] how to retrive value in dropdownlist

问题描述

我必须审核数据库中的更改。在大多数页面上，这是完美的，因为只有文本框 - 但是在我正在处理的页面上，使用下拉列表，我的代码不起作用。

 <   td   >  
 <   asp：DropDownList     ID   =  DropDownList4     runat   = < span class =code-keyword> server    DataSourceID   =  SqlDatacountry    DataTextField   =  country_name    DataValueField   =  country_id > ;  
 
 
 <   asp：SqlDataSource     ID   =  SqlDatacountry    runat   =  server      ConnectionString   =  <％ $ ConnectionStrings：songtypecons％>    SelectCommand   =  SELECT * FROM [country_detail] >  
 <  < span class =code-leadattribute> / td  >  

代码落后：< br $>

  string  sql1 =    selectcust_fname，cust_mname，cust_lname，cust_birthdate，cust_gender，cust_address，cust_contact_num，cust_country，cust_state，cust_city，cust_zip from cust_detail where cust_id =' + ds。表[  filldata]。行[ 0 ]。ItemArray [ 0 ]。ToString（）+  '; 
 SqlDataAdapter adpt1 =  new  SqlDataAdapter（sql1，con）; 
 DataSet ds1 =  new  DataSet（）; 
 adpt1.Fill（ds1，  custdata）; 
  if （ds1.Tables [  custdata ]。Rows.Count >   0 ）
 {
 
  for （ int  d =  0 ; d <  DropDownList4.Items.Count; d ++）
 {
  if （ds1.Tables [  custdata]。行[ 0 ]。ItemArray [ 7 ]。ToString（）== DropDownList4.Items [d] .Text）
 {
 DropDownList4.Items [d] .Selected =  true ; 
  break ; 
} 
} 
} 

解决方案

ConnectionStrings：songtypecons％> SelectCommand = SELECT * FROM [country_detail] >
< / td >

code背后：

  string  sql1 =   selectcust_fname，cust_mname，cust_lname，cust_birthdate，cust_gender，cust_address，cust_contact_num，cust_country，cust_state，cust_city，cust_zip from cust_detail where cust_id =' + ds.Tables [  filldata]。行[ 0 ]。项目数组[ 0 ]。ToString（）+  ' ; 
 SqlDataAdapter adpt1 =  new  SqlDataAdapter（sql1，con）; 
 DataSet ds1 =  new  DataSet（）; 
 adpt1.Fill（ds1，  custdata）; 
  if （ds1.Tables [  custdata ]。Rows.Count >   0 ）
 {
 
  for （ int  d =  0 ; d <  DropDownList4.Items.Count; d ++）
 {
  if （ds1.Tables [  custdata]。行[ 0 ]。ItemArray [ 7 ]。ToString（）== DropDownList4.Items [d] .Text）
 {
 DropDownList4.Items [d] .Selected =  true ; 
  break ; 
} 
} 
} 

使用DropDownList的SelectedValue属性。

 <   asp：scriptmanager     id   =  ScriptManager1    runat   =  server    xmlns：asp   = ＃unknown    /  >  
 <   asp：updatepanel     runat   =  server    id   =  UpdatePanel1    xmlns：asp   = ＃unknown >  
 <   contenttemplate  >  
 <   asp：dropdownlist     runat   =  server    id   = < span class =code-keyword> ddlCaseFilesNew    datasourceid   =  dsCaseFiles >  
 DataTextField =显示DataValueField =FileIDOnPreRender =ddl_PreRenderWidth =300px
 AutoPostBack =trueOnSelectedIndexChanged =ddlCaseFilesNew_SelectedIndexChangedVisible =False> 
 <   asp：listitem  > 项目1 <   / asp：listitem  > ;  
 <   / asp：dropdownlist  >  
 <   / contenttemplate  >  
 <  触发器 >  
 <   asp：asyncpostbacktrigger  < span class =code-attribute>   controlid   =  ddlCaseFilesNew     eventname   = < span class =code-keyword> SelectedIndexChanged    /  >  
 <   / triggers  >  
 <   / asp：updatepanel  >  
 
 
 <   script       runat   = 服务器 >  
 protected void ddlCaseFilesNew_SelectedIndexChanged（object sender，EventArgs e）
 {
 hidNewCaseFile.Value = ddlCaseFilesNew.SelectedItem.Value; 
} 
 <   / script  >  

I must audit the changes into a database. On most pages this works perfect, as there were just textboxes - however on a page I am working on right now, with dropdownlists, my code isn''t working.

<td>
  <asp:DropDownList ID="DropDownList4" runat="server" DataSourceID="SqlDatacountry" DataTextField="country_name" DataValueField="country_id">
  

  <asp:SqlDataSource ID="SqlDatacountry" runat="server"  ConnectionString="<%$ ConnectionStrings:songtypecons %>" SelectCommand="SELECT * FROM [country_detail]">
</td>

code behind:

string sql1 = "selectcust_fname,cust_mname,cust_lname,cust_birthdate,cust_gender,cust_address,cust_contact_num,cust_country,cust_state,cust_city,cust_zip from cust_detail where cust_id ='" + ds.Tables["filldata"].Rows[0].ItemArray[0].ToString() + "' ";
            SqlDataAdapter adpt1 = new SqlDataAdapter(sql1, con);
            DataSet ds1 = new DataSet();
            adpt1.Fill(ds1, "custdata");
            if (ds1.Tables["custdata"].Rows.Count > 0)
            {

             for (int d = 0; d < DropDownList4.Items.Count; d++)
            {
               if (ds1.Tables["custdata"].Rows[0].ItemArray[7].ToString() == DropDownList4.Items[d].Text)
              {
                   DropDownList4.Items[d].Selected = true;
                   break;
               }
           }
        }

解决方案

ConnectionStrings:songtypecons %>" SelectCommand="SELECT * FROM [country_detail]"> </td>

code behind:

string sql1 = "selectcust_fname,cust_mname,cust_lname,cust_birthdate,cust_gender,cust_address,cust_contact_num,cust_country,cust_state,cust_city,cust_zip from cust_detail where cust_id ='" + ds.Tables["filldata"].Rows[0].ItemArray[0].ToString() + "' ";
            SqlDataAdapter adpt1 = new SqlDataAdapter(sql1, con);
            DataSet ds1 = new DataSet();
            adpt1.Fill(ds1, "custdata");
            if (ds1.Tables["custdata"].Rows.Count > 0)
            {

             for (int d = 0; d < DropDownList4.Items.Count; d++)
            {
               if (ds1.Tables["custdata"].Rows[0].ItemArray[7].ToString() == DropDownList4.Items[d].Text)
              {
                   DropDownList4.Items[d].Selected = true;
                   break;
               }
           }
        }

Use SelectedValue property of DropDownList.

<asp:scriptmanager id="ScriptManager1" runat="server" xmlns:asp="#unknown" />
    <asp:updatepanel runat="server" id="UpdatePanel1" xmlns:asp="#unknown">
        <contenttemplate>
            <asp:dropdownlist runat="server" id="ddlCaseFilesNew" datasourceid="dsCaseFiles">
                DataTextField="Display" DataValueField="FileID" OnPreRender="ddl_PreRender" Width="300px"
                AutoPostBack="true" OnSelectedIndexChanged="ddlCaseFilesNew_SelectedIndexChanged" Visible="False">
                <asp:listitem>Item 1</asp:listitem>
            </asp:dropdownlist>
        </contenttemplate>
        <triggers>
            <asp:asyncpostbacktrigger controlid="ddlCaseFilesNew" eventname="SelectedIndexChanged" />
        </triggers>
    </asp:updatepanel>


<script  runat="server">
    protected void ddlCaseFilesNew_SelectedIndexChanged(object sender, EventArgs e)
    {
        hidNewCaseFile.Value = ddlCaseFilesNew.SelectedItem.Value;
    }
</script>

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