[转]dropdownlist动态绑定数据方法 添加默认项“请选择”

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《一》动态绑定方法

4 D# i# O$ [' y4 NddlItems.DataSource = voe.SelectItems();
! m. ]  Q1 P, p5 addlItems.DataTextField = "VoteItem";
( U5 j9 k2 B6 _# ^+ ]0 uddlItems.DataValueField = "VoteId";
8 f+ v$ R9 E$ r/ FddlItems.DataBind();

8 [2 C- K* r5 _1 X' |" X0 N《二》添加默认项“请选择”

' x( k, w) p4 O# x' G方法1
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绑定后添加
6 E: o+ q- U' s+ B, qListItem lt = new ListItem();
; V9 U) e) U  S! C9 l" _lt.Text = "请选择";
& R! ?5 N  {! s' X  N5 s; ~5 rlt.Value = "00";
8 a5 _; {. |0 B4 e6 S7 Hlt.Selected = true;
  ~' @( l1 b* a. mddl.Items.Add(lt);
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& N2 B( W6 J( c+ ]. Z放到databind()之后
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" n2 Y6 ~5 R, O6 ^方法2

. r) S. C) k7 b& n! b9 z绑定以后添加下面代码：
ListItem it = new ListItem("请选择", "0");
1 z2 r& b: X* p3 Z2 lddl.Items.Insert(0,it);

《三》绑定后指定第一项

) D3 `: I! A  ?8 w' _8 R+ {ddlItems.DataSource = voe.SelectItems();
ddlItems.DataTextField = "VoteItem";
+ S" M# T0 K6 X4 z" QddlItems.DataValueField = "VoteId";
ddlItems.DataBind();
4 o' i* H+ o! c, M# C1 |string str="你想要的文本";
8 ^! e3 W6 p0 q6 V5 `3 X/ eint index = this.ddl.Items.IndexOf(this.ddl.Items.FindByText(str));
ddl.SelectedIndex = index;

* A# ]# i' b0 O4 M) g0 j  Z9 c' o《三》绑定后指定第一项
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" Q8 c% V7 a4 h0 n, BddlItems.DataSource = voe.SelectItems();
ddlItems.DataTextField = "VoteItem";
3 ]% u0 {, [% D% C) J- k- ?ddlItems.DataValueField = "VoteId";
! [- ~& R% i, n7 Q" p& y7 a* P: OddlItems.DataBind();
string vID = Request.QueryString["id"];
  J4 O% ~; u9 h8 X0 `" tddl.SelectedValue= vID;