指定的转换无效？？？

objArgs.Item.Cells[1].Controls[0]是TEXTBOX嘛？

“int”并不包含对“Prase”的定义

我是照着asp.net高级编程里的例子写的，例子没问题

是这一句转换无效
TextBox objauid1 = (TextBox)objArgs.Item.Cells[1].Controls[0];

设个断点
在Watch中看objArgs.Item.Cells[1].Controls[0]是什么类型的

找找呗，看看objArgs.Item.Cells[1].Controls[1]; 或者Controls[2]...
一般来说，肯定会有。反正错误显示，Controls[0]肯定不是一个TextBox。

1,检查objArgs.Item.Cells[1]里是什么控件，不是TextBox肯定无效
2，用这种方式
TextBox objauid1 = (TextBox)objArgs.Item.Cells[1].FindControl("控件id");
不行吗

下面的原例子的代码
<%@Page Language="C#"%><%@Import Namespace="System.Data" %>
<%@Import Namespace="System.Data.OleDb" %><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<html><head>
<title>Editing Data in a DataGrid Control</title>
<style type="text/css">
body, td {font-family:Tahoma,Arial,sans-serif; font-size:10pt}
input {font-family:Tahoma,Arial,sans-serif; font-size:9pt}
.heading {font-family:Tahoma,Arial,sans-serif; font-size:14pt; font-weight:bold}
.subhead {font-family:Tahoma,Arial,sans-serif; font-size:12pt; font-weight:bold; padding-bottom:5px}
.cite {font-family:Tahoma,Arial,sans-serif; font-size:8pt}.rHead {font-family:Lucida Handwriting,Comic Sans MS,Tahoma,Arial;
        font-size:14pt; font-weight:bold; padding:8px; color:green}
.rItem {font-family:Lucida Handwriting,Comic Sans MS,Tahoma,Arial,sans-serif;
        font-size:10pt}
.rFoot {font-family:Tahoma,Arial; font-size:8pt; padding:8px; color:darkgray}</style></head>
<body bgcolor="#ffffff">
<span class="heading">Editing Data in a DataGrid Control</span><hr />
<div id="outError" runat="server" /><ASP:Label id="lblSQL" runat="server" /><p /><form runat="server">  <ASP:DataGrid id="MyDataGrid" runat="server"
       CellPadding = "2"
       EditItemStyle-BackColor="yellow"
       DataKeyField="ISBN"
       OnEditCommand="DoItemEdit"
       OnUpdateCommand="DoItemUpdate"
       OnCancelCommand="DoItemCancel"
       AutoGenerateColumns="False">    <Columns>      <ASP:BoundColumn DataField="ISBN" HeaderText="ISBN" ReadOnly="True" />      <ASP:TemplateColumn HeaderText="Title">
        <ItemTemplate>
          <ASP:Label Text='<%# DataBinder.Eval(Container.DataItem, "Title") %>' runat="server" />
        </ItemTemplate>
        <EditItemTemplate>
          <ASP:TextBox id="txtTitle" Size="60"
               Text='<%# DataBinder.Eval(Container.DataItem, "Title") %>' runat="server" />
        </EditItemTemplate>
      </ASP:TemplateColumn>      <ASP:BoundColumn DataField="PublicationDate" HeaderText="Published" />      <ASP:EditCommandColumn
           EditText="Edit"
           CancelText="Cancel"
           UpdateText="Update" />    </Columns>  </ASP:DataGrid></form><script language="C#" runat="server">  void Page_Load(Object sender, EventArgs e)
  {
    if (!Page.IsPostBack)
      BindDataGrid();   // create data set and bind to grid control
  }
  void DoItemEdit(Object objSource, DataGridCommandEventArgs objArgs)
  {
    lblSQL.Text = "";   // clear text from label that shows SQL statement    // set the EditItemIndex property of the grid to this item's index
    MyDataGrid.EditItemIndex = objArgs.Item.ItemIndex;
    BindDataGrid();   // bind the data and display it
  }
  void DoItemUpdate(Object objSource, DataGridCommandEventArgs objArgs)
  {
    // get a reference to the title and publication date text boxes
    TextBox objTitleCtrl = (TextBox)objArgs.Item.FindControl("txtTitle");
    TextBox objPubDateCtrl = (TextBox)objArgs.Item.Cells[2].Controls[0];    // create a suitable SQL statement and execute it
    string strSQL = "UPDATE Booklist SET Title='" + objTitleCtrl.Text + "', "
          + "PublicationDate='" + objPubDateCtrl.Text + "' "
          + "WHERE ISBN='" + MyDataGrid.DataKeys[objArgs.Item.ItemIndex] + "'";
    ExecuteSQLStatement(strSQL);    // set EditItemIndex property of grid to -1 to switch out of Edit mode
    MyDataGrid.EditItemIndex = -1;
    BindDataGrid();   // bind the data and display it
  }
  void DoItemCancel(Object objSource, DataGridCommandEventArgs objArgs)
  {
    // set EditItemIndex property of grid to -1 to switch out of Edit mode
    MyDataGrid.EditItemIndex = -1;
    BindDataGrid();   // bind the data and display it
  }
  void ExecuteSQLStatement(string strSQL)
  {
    // this is where the SQL statement would be executed against the
    // original data source. In this example, we're simply displaying
    // the statement in a Label on the page
    lblSQL.Text = "<b>The SQL statement that would be executed is:</b><br />" + strSQL;
  }
  void BindDataGrid()
  {
    // get connection string from web.config
    string strConnect = ConfigurationSettings.AppSettings["DsnWroxBooksOleDb"];    // create a SQL statement to select some rows from the database
    string strSelect = "SELECT * FROM BookList WHERE ISBN LIKE '%7%'";    // create a variable to hold an instance of a DataReader object
    OleDbDataReader objDataReader;    try
    {
      // create a new Connection object using the connection string
      OleDbConnection objConnect = new OleDbConnection(strConnect);      // open the connection to the database
      objConnect.Open();      // create a new Command using the connection object and select statement
      OleDbCommand objCommand = new OleDbCommand(strSelect, objConnect);      // execute the SQL statement against the command to get the DataReader
      objDataReader = objCommand.ExecuteReader();
    }
    catch (Exception objError)
    {
      // display error details
      outError.InnerHtml = "<b>* Error while accessing data</b>.<br />"
                + objError.Message + "<br />" + objError.Source + "<p />";
      return;   //  and stop execution
    }    // set the DataSource property and bind the grid
    MyDataGrid.DataSource = objDataReader;
    MyDataGrid.DataBind();
  }</script>
<hr /><span class="cite">[<a href="../global/viewsource.aspx">view source</a>]        
+copy;2004 <a class="cite" href="http://www.wrox.com/">Wrox Press</a> -
<a class="cite" href="http://www.wrox.com/books/0764558900.shtml">Professional ASP.NET 1.1</a> (ISBN: 0-7645-5890-0)</span>
</body>
</html>可以运行

objArgs.Item.Cells[1].Controls[0]---->objArgs.Item.Cells[1].Controls[1]

objArgs.Item.Cells[1].Controls[1]=objArgs.Item.FindControl("auid2")
都是修改后的值修改前的值无法拿到

行 39： TextBox objauid2 = (TextBox)objArgs.Item.FindControl("auid2");//行 40： //TextBox objauid1 = (TextBox)objArgs.Item.FindControl("auid1");
行 41： TextBox objauid1 = (TextBox)objArgs.Item.Cells[1].Controls[0];
行 42：
行 43： string strconn = "update Authors SET au_id='"+objauid2.Text+"' WHRER au_id='"+objauid1.Text+"'";检查auid2、auid1、objArgs.Item.Cells[1].Controls[0];这三个控件是否是TextBox
检查字段au_id是int型还是char型

调试易

指定的转换无效？？？

解决方案 »