[转]dropdownlist动态绑定数据方法 添加默认项“请选择”

Star

《一》动态绑定方法
, H5 a% H  O1 k8 e5 F: u7 \, X
6 ^( V6 T$ m, p4 ~$ YddlItems.DataSource = voe.SelectItems();
ddlItems.DataTextField = "VoteItem";
ddlItems.DataValueField = "VoteId";
4 I: _7 O- ^9 ]( b0 qddlItems.DataBind();
$ X" H4 }' g1 Y( X  s
《二》添加默认项“请选择”

方法1
; y# L+ C8 b" c
# c! D2 i2 G- p6 f. E绑定后添加
ListItem lt = new ListItem();
lt.Text = "请选择";
8 [% D0 A/ |8 z1 Y% T3 Rlt.Value = "00";
$ X2 r, x# U, |8 k, c- `lt.Selected = true;
: d: ^9 Q/ U; w/ ?; y& |: O. wddl.Items.Add(lt);
5 W# V) Y( l2 F% w& ~" g
放到databind()之后

" C8 x4 ^1 d% L0 u0 i0 E方法2
9 t2 r6 A8 j4 f1 Z- i/ Y$ v' X* l
- z: a9 _" p& d  g1 h5 h绑定以后添加下面代码：
ListItem it = new ListItem("请选择", "0");
3 ]/ N" a6 x9 i, G# rddl.Items.Insert(0,it);
4 d, s5 e: U9 N3 [& W6 e! x9 |  m: E3 o# V, }
《三》绑定后指定第一项

ddlItems.DataSource = voe.SelectItems();
ddlItems.DataTextField = "VoteItem";
ddlItems.DataValueField = "VoteId";
5 W, d$ O( U6 z; BddlItems.DataBind();
# {9 O. X, c; g+ Tstring str="你想要的文本";
/ Z8 q+ P0 b& j/ z* fint index = this.ddl.Items.IndexOf(this.ddl.Items.FindByText(str));
ddl.SelectedIndex = index;

《三》绑定后指定第一项

! q+ c( r/ O0 A. F* I2 ~ddlItems.DataSource = voe.SelectItems();
ddlItems.DataTextField = "VoteItem";
8 [! o7 C0 S# XddlItems.DataValueField = "VoteId";
ddlItems.DataBind();
3 N, y2 ?- f5 _! h6 \string vID = Request.QueryString["id"];
8 H7 `9 H0 \3 H! O( Q+ P" M( Rddl.SelectedValue= vID;