如何以格式化方式在gridview中添加下拉列表 [英] How to add dropdownlist in gridview programetically

问题描述

我有如下加载事件：

I have load event as follow:

protected void Page_Load(object sender, EventArgs e)
    {

        SqlConnection con = new SqlConnection("Data Source=.\\sqlexpress;Initial Catalog=testdb;Integrated Security=True;Pooling=False");
        con.Open();
        SqlDataAdapter da = new SqlDataAdapter("select * from emp",con);
        DataSet ds = new DataSet();
        da.Fill(ds);
        GV_DataByGroupAct.DataSource =ds.Tables[0]; 
        GV_DataByGroupAct.DataBind();
    }

查看源视图：

Have look of source view:

<asp:GridView ID="GV_DataByGroupAct" runat="server" AutoGenerateColumns="true"

        onrowdatabound="GV_DataByGroupAct_RowDataBound">
        <Columns>

</Columns>
    </asp:GridView>

和GV_DataByGroupAct_RowDataBound事件：

And GV_DataByGroupAct_RowDataBound event:

protected void GV_DataByGroupAct_RowDataBound(object sender, GridViewRowEventArgs e)
    {

        if (e.Row.RowType == DataControlRowType.DataRow)
        {
            foreach (TableCell tc in e.Row.Cells)
            {
                dl = new DropDownList();
                dl.Items.Add("one");
                dl.Items.Add("two");
                dl.Items.Add("three");

                tc.Controls.Add(dl);
            }
        }

    }

当我运行它时，它只向网格视图添加下拉列表控件。

我只是尝试将数据库中的数据以及下拉列表添加到新列中的每一行。请建议。

As i run this it adds only dropdownlist control to the gridview.
I am just trying to add data from database as well as dropdownlist to each rows in a new column. Please suggest.

推荐答案

首先，你应该检查 Page_Load上的 IsPostBack 属性。

First of all, you should check IsPostBack property on Page_Load.

protected void Page_Load(object sender, EventArgs e)
{
     If(!IsPostBack)
     {
        SqlConnection con = new SqlConnection("Data Source=.\\sqlexpress;Initial Catalog=testdb;Integrated Security=True;Pooling=False");
        con.Open();
        SqlDataAdapter da = new SqlDataAdapter("select * from emp",con);
        DataSet ds = new DataSet();
        da.Fill(ds);
        GV_DataByGroupAct.DataSource =ds.Tables[0]; 
        GV_DataByGroupAct.DataBind();
     }
}

在 RowDataBound 中，您正在为所有单元格循环，但是您应该只循环行。

这可能是它在所有单元格上显示的原因。

In RowDataBound, you are looping for all cells, but you should only loop for the rows.
That may be the reason it is showing on all cells.

做一些事情如下：

我认为唯一的问题是性能下降，不是吗？有人有解决方案吗？

Well do some thing like follow:
Only problem i think would be is performance degrade, isn't? anyone has some solution?

<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False"

           DataKeyNames="EmpId" DataSourceID="SqlDataSource1"

           ondatabound="GridView1_DataBound">
           <Columns>
               <asp:CommandField ShowSelectButton="True" />

               <asp:BoundField DataField="EmpId" HeaderText="EmpId" ReadOnly="True"

                   SortExpression="EmpId" />
                   <asp:BoundField  HeaderText="Category" />
               <asp:BoundField DataField="Name" HeaderText="Name" SortExpression="Name" />
           </Columns>
       </asp:GridView>
       <asp:SqlDataSource ID="SqlDataSource1" runat="server"

           ConnectionString="<%

ConnectionStrings：DatabaseConnectionString ％> ;

SelectCommand = SELECT * FROM [employee] > < / asp：SqlDataSource >

ConnectionStrings:DatabaseConnectionString %>" SelectCommand="SELECT * FROM [employee]"></asp:SqlDataSource>

< br $> b $ b

protected void Page_Load(object sender, EventArgs e)
   {
       if(IsPostBack)
       addControl();
   }
   void addControl()
   {

       foreach (GridViewRow row in GridView1.Rows)
       {
           if (row.RowType == DataControlRowType.DataRow)
           {
               DropDownList dl = new DropDownList();
               dl.Items.Add("One");
               dl.Items.Add("Two");
               row.Cells[2].Controls.Add(dl);
           }
       }
   }
   protected void GridView1_DataBound(object sender, EventArgs e)
   {

       addControl();
   }

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