Question

C# .net Dropdownlist 设置首选项为空

if (null != datset && 0 < datset.Tables[0].Rows.Count)
{
ddlTempTianbaoren.DataSource = datset;
ddlTempTianbaoren.DataTextField = "姓名";
ddlTempTianbaoren.DataBind();
ddlTempTianbaoren.SelectedIndex = -1;
ddlTempTianbaoren.Text = string.Empty;
}
这样写的没有效果，改怎么实现呢？

Answer 1

使用重定义代码，即可设置首选项为空。代码如下：
ddlTempTianbaoren.DataSource = datset;
ddlTempTianbaoren.DataTextField = "姓名";
ddlTempTianbaoren.DataBind();
ddlTempTianbaoren.Items.Insert(0, new ListItem());

Answer 2

　　

1 ddlTempTianbaoren.DataSource = datset;
2 ddlTempTianbaoren.DataTextField = "姓名";
3 ddlTempTianbaoren.DataBind();
4 ddlTempTianbaoren.Items.Insert(0, new ListItem());

Answer 3

ddlTempTianbaoren.DataSource = datset;
ddlTempTianbaoren.DataTextField = "姓名";
ddlTempTianbaoren.DataBind();
ddlTempTianbaoren.Items.Insert(0, new ListItem());