selectedvalueasp.net SelectedIndex和SelectedValue的区别

selectedvalue 时间:2021-07-20 阅读:()

<option value="" selected="selected" >selected作用

<!DOCTYPE?HTML> <html?lang="en-US"> <head> <meta?charset="UTF-8"> <title>menu</title> <style?type="text/css"> </style> <script?type="text/javascript"> </script> </head> <body> <select> <option>ddfdf</option>  <option?value=""?selected="selected">aaa</option> <option>dd</option> </select> </body> </html>

DropDownList2.SelectedValue.Trim()什么意思

DropDownList2控件，的SelectedValue属性（选中的值）是一个字符串然后Trim()函数是去除字符串两端的空白字符连起来就是得到DropDownList2控件选中项值去除两端空白的字符串

asp.net SelectedIndex和SelectedValue的区别

protected void Page_Load(object sender, EventArgs e) { if (!IsPostBack) { DropDownList1.Items.Insert(0, "123");//为DropDownList1的第一项添加"123" DropDownList1.Items.Insert(1, "456"); } } protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e) { if (DropDownList1.SelectedIndex== 0)//选择了第一项 { Response.Write("" + DropDownList1.SelectedValue.ToString() + ""); } if (DropDownList1.SelectedValue.ToString() == "456")//选择了名为456的项 { Response.Write("" + DropDownList1.SelectedValue.ToString() + ""); } } 一句话说来就是SelectedIndex索引的是项，SelectedValue索引的是变量

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