您可以将 DropDownList 绑定到数据源(DataTable、List、DataSet、SqlDataSource 等)。
例如,如果您想使用数据表:
ddlSubject.DataSource = subjectsTable;
ddlSubject.DataTextField = "SubjectNamne";
ddlSubject.DataValueField = "SubjectID";
ddlSubject.DataBind();
编辑 - 更完整的示例
private void LoadSubjects()
{
DataTable subjects = new DataTable();
using (SqlConnection con = new SqlConnection(connectionString))
{
try
{
SqlDataAdapter adapter = new SqlDataAdapter("SELECT SubjectID, SubjectName FROM Students.dbo.Subjects", con);
adapter.Fill(subjects);
ddlSubject.DataSource = subjects;
ddlSubject.DataTextField = "SubjectNamne";
ddlSubject.DataValueField = "SubjectID";
ddlSubject.DataBind();
}
catch (Exception ex)
{
// Handle the error
}
}
// Add the initial item - you can add this even if the options from the
// db were not successfully loaded
ddlSubject.Items.Insert(0, new ListItem("<Select Subject>", "0"));
}
要通过标记(而不是代码隐藏)设置初始值,请指定选项并将 AppendDataBoundItems 属性设置为 true:
<asp:DropDownList ID="ddlSubject" runat="server" AppendDataBoundItems="true">
<asp:ListItem Text="<Select Subject>" Value="0" />
</asp:DropDownList>
然后,您可以将 DropDownList 绑定到代码隐藏中的数据源(只需记住删除:
ddlSubject.Items.Insert(0, new ListItem("<Select Subject>", "0"));
从代码隐藏中,否则您将有两个“”项。