如何从c＃中的下拉列表绑定trhough jquery中获取所选文本

Question

我希望从下拉列表中选择文本，其中数据通过jQuery绑定，并在c＃函数中用于显示。

页面设计和jquery调用函数

<script src="../../JavaScript/jquery-3.1.1.min.js"></script>
<script type="text/javascript">
    $(function () {
        $("[id*=ddlCountry]").change(function (e) {
            $.ajax({
                type: "POST",
                url: "testing.aspx/getstateList",
                data: '{value: "' + $(this).val() + '"}',
                contentType: "application/json; charset=utf-8",
                dataType: "json",
                success: function (r) {
                    var ddlCustomers = $("[id*=ddlState]");
                    ddlCustomers.empty().append('<option selected="selected" value="">Select an State</option>');
                    $.each(r.d, function () {
                        ddlCustomers.append($("<option></option>").val(this['Value']).html(this['Text']));
                    });
                }
            })
        })
    });
</script>

<form id="form1" runat="server">

            <label for="validate-select">Country Name:</label>
                <asp:DropDownList ID="ddlCountry" runat="server" >
                    <asp:ListItem Value="">Select an Country</asp:ListItem>
                </asp:DropDownList>

            <label for="validate-select">State Name:</label>
                <asp:DropDownList ID="ddlState" runat="server">
                    <asp:ListItem Value="">Select an State</asp:ListItem>
                </asp:DropDownList>



        <asp:Button ID="btnsave" runat="server" Text="Submit" OnClick="btnsave_Click"  />     

使用webmethod从数据库表中获取数据

 [WebMethod]
public static List<ListItem> getstateList(string value)
{
    SqlConnection strConnection = new SqlConnection("connection string"); 
    strConnection.Open();

    SqlCommand cmd = new SqlCommand("select state_name as 'output', id from stateMaster where country_id='101' and Status='ACTIVE' order by state_name", strConnection);   

    List<ListItem> customers = new List<ListItem>();

    SqlDataReader sdr = cmd.ExecuteReader();//opr.getDataReaderTrans("select state_name as 'output', id from stateMaster where country_id='101' and Status='ACTIVE' order by state_name");

    while (sdr.Read())
    {
        customers.Add(new ListItem
        {
            Value = sdr["id"].ToString(),
            Text = sdr["output"].ToString()
        });
    }
    return customers;
}
protected void btnsave_Click(object sender, EventArgs e)
{
    string state = ddlState.SelectedItem.Text;

    Response.Write(state);
}

Answer 1

您可以使用dropdownlist.SelectedItem.Text获取所选项目的文本，并使用dropdownlist.SelectedValue获取所选项目的值。

检查以下样本：

protected void btnsave_Click(object sender, EventArgs e)
{
    //Retrieve Selected Text from Dropdown
    var countrySelText = ddlCountry.SelectedItem.Text;
    //Retrieve Selected Value from Dropdown
    var countrySelValue = ddlCountry.SelectedValue;

    //Retrieve Selected Text from Dropdown
    var stateSelText = ddlState.SelectedItem.Text;
    //Retrieve Selected Value from Dropdown
    var stateSelValue = ddlState.SelectedValue;
}

Answer 2

获取您可以使用的选定文本：

var _Selected = document.getElementById("yourdropdownID");
var _SelectedIndex = _Selected.options[_Selected.selectedIndex].text;

或者如果你想获得价值：

var _Selected = document.getElementById("yourdropdownID");
var _SelectedIndex = _Selected.options[_Selected.selectedIndex].value;