为什么 点击Button会将 动态生成的DropDownList中不绑定的数据清空？

[M057612]

为什么 点击Button会将 动态生成的DropDownList中不绑定的数据清空？

  for (int i = 0; i < temp; ++i)
        {
            this.NewTableRow(i);
        }

  protected void NewTableRow(int i)
    {
        TableRow tr = new TableRow();
       
        TableCell tc;
        TextBox tb;
        Label td;
        DropDownList tl;

        int rowqty = i + 1;

        tc = new TableCell();
        td = new Label();
        td.CssClass = "FieldStyle";
        td.ID = "txtDel" + i;
        
        td.Text = "" + rowqty;
        tc.Controls.Add(td);
        tr.Cells.Add(tc);

        tc = new TableCell();
        tb = new TextBox();
        tb.CssClass = "FieldStyle"; 
        tb.ID = "txtItemno" + i;
        tb.Attributes.Add("ondblclick", "getItem('" + i + "');");
        tb.Attributes.Add("onclick", "getSelect('txtItemno"+ i + "');");
        tc.Controls.Add(tb);
        tr.Cells.Add(tc);

        tc = new TableCell();
        tb = new TextBox();
        
        tb.CssClass = "FieldStyle";
        tb.TextMode = TextBoxMode.MultiLine;
        tb.Rows = 2;
        tb.ID = "txtDes" + i;
        tb.Attributes.Add("onblur", "getfu('txtDes" + i + "');");
        tc.Controls.Add(tb);
        tr.Cells.Add(tc);

        tc = new TableCell();
        tb = new TextBox();
        tb.CssClass = "FieldStyle";
        tb.ID = "txtModel" + i;
        tb.Attributes.Add("onblur", "getfu('txtModel" + i + "');");
        tc.Controls.Add(tb);
        tr.Cells.Add(tc);

        tc = new TableCell();
        tb = new TextBox();
        tb.CssClass = "FieldStyle";
        tb.ID = "txtQty" + i;
        tb.Attributes.Add("onblur", "getsum('txtQty" + i + "');");
        tb.Attributes.Add("onclick", "getSelect('txtQty" + i + "');");
        tc.Controls.Add(tb);
        tr.Cells.Add(tc);

        tc = new TableCell();
        tb = new TextBox();
        tb.CssClass = "FieldStyle";
        tb.ID = "txtUOM" + i;
        tc.Controls.Add(tb);
        tr.Cells.Add(tc);

        tc = new TableCell();
        tb = new TextBox();
        tb.CssClass = "FieldStyle";
        //tb.ReadOnly = true;
        tb.ID = "txtDate" + i;
        tb.Attributes.Add("onclick","SelectDate(this,'yyyy-MM-dd')");
        tc.Controls.Add(tb);
        tr.Cells.Add(tc);

        tc = new TableCell();
        tb = new TextBox();
        tb.CssClass = "FieldStyle";
        tb.ID = "txtUPrice" + i;
        tb.Attributes.Add("onblur", "getsum('txtUprice" + i + "');");
        tb.Attributes.Add("onclick", "getSelect('txtUprice" + i + "');");
        tc.Controls.Add(tb);
        tr.Cells.Add(tc);


        tc = new TableCell();
        tb = new TextBox();
        tb.CssClass = "FieldStyle";
        tb.ID = "txtAccount" + i;
        tc.Controls.Add(tb);
        tr.Cells.Add(tc);

        tc = new TableCell();
        tb = new TextBox();
        tb.CssClass = "FieldStyle";
        tb.ID = "txtQuote" + i;
        tc.Controls.Add(tb);
        tr.Cells.Add(tc);

        /*tc = new TableCell();
        tb = new TextBox();
        tb.CssClass = "FieldStyle";
        tb.ID = "txtBuyer" + i;
        tb.ReadOnly();
        tc.Controls.Add(tb);
        tr.Cells.Add(tc);*/

        tc = new TableCell();

        tl = new DropDownList();
        tl.CssClass = "FieldStyle";
        tl.ID = "txtBuyer" + i;
       // tl.Style.Add("height", "21px");
        for (int j = 0; j < tBuyer.Length; j++)
        {
            if (tBuyer[j]=="" | tBuyer[j]==null)
                break;
         tl.Items.Add(new ListItem(tBuyer[j],tBuyer[j]));
        }
        tr.Cells.Add(tc);
        tc.Controls.Add(tl);



        //DropDownList("txtBuyer" + i).DataSource = tBuyer;
        //DropDownList("txtBuyer" + i).DataBind();
       // Enumerable.Range(1, 10).Select("txtBuyer" + i).ToList().ForEach(tl.Items.Add(i));
 


        this.m_table.Rows.Add(tr);

    }


    protected void btnAddDetail_Click(object sender, EventArgs e)
    {
       
            this.NewTableRow(this.Num++);
            Label1.Text = this.Num.ToString();
       
    }

[bdmh]

引发了页面重新加载，因为是服务端组件，将数据绑定放到pageload中，加上判断 ispostback

[骑着蜗牛去爬山]

重新绑定一下dropdownlist

[流浪的麻雀]

Button会是服务器控件，引发了页面回发，要么在pageload加上if(！ispostBack）｛绑定数据｝，要么，点击Button后，重新绑定。

[M057612]

引用 1 楼 bdmh 的回复:

引发了页面重新加载，因为是服务端组件，将数据绑定放到pageload中，加上判断 ispostback

[M057612]

我是点击按钮动态添加的，不能放在page_load中，怎么办啊