DropdownList数据源

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DropdownList数据源

大家好，我对下拉列表有疑问。我正在将下拉列表与数据源一起使用。如何获得所选的值？

// I need a if statement here because my programme doesn't know which value of dropdown list selected and I don't know how to use this with datasource.

if(//if I select quiz 1 from dropdown list ,quiz 1 should list questions.)

SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["RegConnectionString"].ConnectionString);

string chooce = "Select Quiz from tblQuiz where Quiz=1 ";
SqlCommand userExist = new SqlCommand(chooce, con);
con.Open();
int temp = Convert.ToInt32(userExist.ExecuteScalar().ToString());

if (temp == 1)
{
    if (rbList.Items[0].Selected == true)
    {
        string cmdStr = "Select Question from tblQuiz where ID=1";
        SqlCommand quest = new SqlCommand(cmdStr, con);
        lblque.Text = quest.ExecuteScalar().ToString();
        con.Close();
    }

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2020-05-19

共1个答案

小编典典

您可以使用来以不同的方式绑定DropDownList List, Dictionary, Enum, DataSet DataTable。
主要在绑定下拉数据源时您必须考虑三件事。

数据源-数据集或数据表或您的数据源的名称
DataValueField-这些字段将被隐藏
DataTextField-这些字段将显示在下拉菜单中。

您可以使用以下代码将下拉列表作为数据绑定到数据源datatable：

  SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["ConnString"].ConnectionString);

    SqlCommand cmd = new SqlCommand("Select * from tblQuiz", con);

    SqlDataAdapter da = new SqlDataAdapter(cmd);

    DataTable dt=new DataTable();
    da.Fill(dt);

    DropDownList1.DataTextField = "QUIZ_Name";
    DropDownList1.DataValueField = "QUIZ_ID"

    DropDownList1.DataSource = dt;
    DropDownList1.DataBind();

如果要处理选择下拉列表，则必须进行更改，然后AutoPostBack="true"可以使用SelectedIndexChangedevent编写代码。

protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
{
    string strQUIZ_ID=DropDownList1.SelectedValue;
    string strQUIZ_Name=DropDownList1.SelectedItem.Text;
    // Your code..............
}

2020-05-19