DataGrid的一个简单问题

Question

我用DataGrid绑定数据的时候，其中有一个是类型ID，我想显示类型名称[在另外一个表]
    protected void ShowTypeName()
    {
        string showSql = "Select * From AD";
        OleDbCommand myCommand = new OleDbCommand(showSql, myConnection);
        myConnection.Open();
        OleDbDataReader dr = myCommand.ExecuteReader();
        while (dr.Read())
        {
            string TypeSql = "Select * From Type Where id = " + dr["Typeid"] + "";
            OleDbCommand myCommand1 = new OleDbCommand(TypeSql, myConnection);
            OleDbDataReader dr1 = myCommand1.ExecuteReader();
            Response.Write(dr["Type"]);
            if (dr1.Read())
            {
                Response.Write(dr1["TypeName"]);
            }
        }
        myConnection.Close();
    }
当我用这个方法来显示类型名称的时候，所有的名称都出来了，怎么才可以显示每条记录对应的类型名称呢

Answer 1

SQL语句用左联接。直接查个完整的数据集。这样效率也高
select a.id,b.name from table a left join table b on a.id = b.id

Answer 2

根据你的要求,大致是这样    protected void ShowTypeName()
    {
        string showSql = "Select ad.Typeid, ad.[type], [type].typeName From AD inner join [Type] on ad.typeid = [type].typeid";
        OleDbCommand myCommand = new OleDbCommand(showSql, myConnection);
        myConnection.Open();
        OleDbDataReader dr = myCommand.ExecuteReader();
        while (dr.Read())
        {
            Response.Write(dr["Type"].ToString() + " " + dr["TypeName"].ToString() + "<br />");
        }
        myConnection.Close();
    }

Answer 3

System.Data.OleDb.OleDbException: 不支持连接表达式
应该怎么修改？

Answer 4

TO高歌：我那两个表的字段ID的类型不一样，出现表达式中的类型不匹配这样的错误，我不想该ACCESS里的类型，那我怎么做呢

Answer 5

那你这两个表关联的字段是不是typeid呢?

Answer 6

Type 里的ID是和AD里的typeid一样，不过类型不一样 

Answer 7

通过select语句转换其中一个typeid的类型,然后关联检索结果到另一个表

Answer 8

Select a.Typeid, a.[type], [type].typeName From (select convert(int,typeid) as typeid,[type] from AD) as a inner join [Type] on ad.typeid = [type].typeid

Answer 9

我修改了类型，OK了
不过还是把所有的类型名称给打印出来了，我这个问题的意思，一个DATAGRID绑定了的，有一列是类型ID显示的，我想把这一列用类型名称给显示出来。

Answer 10

Select ad.Typeid, ad.[type], [type].typeName From AD inner join [Type] on ad.typeid = [type].typeid
=====
假设你的ad表的typeid是文本类型Select ad.Typeid, ad.[type], [type].typeName From AD , [Type] on ad.typeid = cstr([type].typeid)如果是其他类型,请参考以下类型转换函数
  cbool(expression)   
    
  cbyte(expression)   
    
  ccur(expression)   
    
  cdate(expression)   
    
  cdbl(expression)   
    
  cdec(expression)   
    
  cint(expression)   
    
  clng(expression)   
    
  csng(expression)   
    
  cstr(expression)   
    
  cvar(expression)   
    
  cstr(expression)

Answer 11

在你的例子中我没见到有什么DataGrid啊

Answer 12

        string mySql = "Select * From AD ";
        myConnection = new OleDbConnection(connectionString);
        OleDbDataAdapter da = new OleDbDataAdapter(mySql, myConnection);
        DataSet ds = new DataSet();
        da.Fill(ds);
        DataGrid1.DataSource = ds.Tables[0];
        DataGrid1.DataBind();首先感谢大家热心的帮助
我是先绑定它，后来在AD里的类型ID我想通过Type表来显示对应的类型名称，也就是自己写个 ShowTypeName()方法，我表达能力不是很好，请见谅

Answer 13

你这样做应该是没有必要的,因为你等于先去了一次数据库得到数据,再去一次数据库去找他的TypeName,实际上应该是第一次就顺便搞定的,你贴贴你的aspx页面的代码看看

Answer 14

<asp:DataGrid runat="server" ID="DataGrid1" AutoGenerateColumns="false" AllowPaging="true"
                                        OnItemDataBound="changeRowColor" PageSize="8" OnPageIndexChanged="NewPage">
                                        <Columns>
                                            <asp:TemplateColumn>
                                                <HeaderTemplate>
                                                    <table width="500px" style="text-align: center;">
                                                        <tr>
                                                            <td style="width: 30px;">
                                                                ID</td>
                                                            <td style="width: 120px;">
                                                                文章类别</td>
                                                            <td style="width: 150px;">
                                                                文章标题</td>
                                                            <td style="width: 50px;">
                                                                点击率</td>
                                                            <td style="width: 50px;">
                                                                是否推荐</td>
                                                            <td style="width: 100px;">
                                                                操作</td>
                                                        </tr>
                                                    </table>
                                                </HeaderTemplate>
                                                <ItemTemplate>
                                                    <table width="500px" style="text-align: center;">
                                                        <tr>
                                                            <td style="width: 30px;">
                                                                <input type="checkbox" name="articleid" value='<%# DataBinder.Eval(Container.DataItem, "ID") %>' /></td>
                                                            <td style="width: 120px;">
                                                                <%ShowTypeName();%>
                                                            </td>
                                                            <td style="width: 150px;">
                                                                <a href="articleShow.aspx?ID=<%#Eval("ID") %>" target="_blank">
                                                                    <%#Eval("Title") %>
                                                                </a>
                                                            </td>
                                                            <td style="width: 50px;">
                                                                <%#Eval("Hit") %>
                                                            </td>
                                                            <td style="width: 50px;">
                                                                <%#Eval("Commend") %>
                                                            </td>
                                                            <td style="width: 100px;">
                                                                <a href="Article_deal.aspx?action=ArticleEdit&amp;ID=<%#Eval("ID") %>">修改</a>&nbsp;|&nbsp;<a
                                                                    href="Article_deal.aspx?action=ArticleDel&amp;ID=<%#Eval("ID") %>" onclick="return confirm('确定删除')">删除</a></td>
                                                        </tr>
                                                    </table>
                                                </ItemTemplate>
                                            </asp:TemplateColumn>
                                        </Columns>
                                        <PagerStyle Mode="NumericPages" />
                                    </asp:DataGrid>
哦 一次搞定，那 da.Fill(ds);DataGrid1.DataSource = ds.Tables[0];
        DataGrid1.DataBind();就有错误，应该怎么修改呢