[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
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8 ^) W3 w6 _4 h- A9 o5 UddlItems.DataSource = voe.SelectItems();
0 I% |* h) g5 ?; O0 a( f9 kddlItems.DataTextField = "VoteItem";
4 d; t" K/ A' d' }% \& l0 e3 _5 w, {ddlItems.DataValueField = "VoteId";
ddlItems.DataBind();

9 _& q# E- I# P. o《二》添加默认项“请选择”
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方法1

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ListItem lt = new ListItem();
+ a  b0 f& g7 R7 g5 z: tlt.Text = "请选择";
, `4 Z0 M3 ~, E) ^4 ^4 N9 L6 Jlt.Value = "00";
, Y! x& W- _& z4 `lt.Selected = true;
ddl.Items.Add(lt);

放到databind()之后

# z3 F2 g6 N% M9 B! F8 W; }方法2
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绑定以后添加下面代码：
ListItem it = new ListItem("请选择", "0");
ddl.Items.Insert(0,it);

3 O0 X" J/ l0 b$ \9 \- H' X4 }# M《三》绑定后指定第一项

! P& v; c, N$ a/ L6 CddlItems.DataSource = voe.SelectItems();
ddlItems.DataTextField = "VoteItem";
- J& Z  K6 W- I: b- }ddlItems.DataValueField = "VoteId";
ddlItems.DataBind();
' f4 W. L0 n% ^0 P( Dstring str="你想要的文本";
int index = this.ddl.Items.IndexOf(this.ddl.Items.FindByText(str));
ddl.SelectedIndex = index;
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《三》绑定后指定第一项
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ddlItems.DataSource = voe.SelectItems();
* Q2 [' s$ E, z# V5 y" D4 AddlItems.DataTextField = "VoteItem";
4 ]- m$ f: l( `( E1 KddlItems.DataValueField = "VoteId";
+ R! d5 L. i, Q8 l) |ddlItems.DataBind();
3 c! d) }& t  E: {1 N6 `2 L* ^string vID = Request.QueryString["id"];
ddl.SelectedValue= vID;