Question

我正在使用jquery向下拉列表添加选项，如下所示。

function GetAssociates(StoreNum,dropdownid) {
        $.ajax({
            type: "POST",
            url: "Appointment.aspx/BindAssociates",
            data: "{storeNumber:" + StoreNum + "}",
            contentType: "application/json; charset=utf-8",
            dataType: "json",
            success: function(result){
                var rs = result.d;
                var select = $("#" + dropdownid);
                //var select = document.getElementById(dropdownid);

                for (var i = 0; i < rs.length; i++) {
                    var opt = rs[i].trim();
                    select.append(new Option(opt,opt));
                }
            },
            error: function(result){
                alert("Failed to load dropdown" + result);
            }
        });
    }

这完美无缺，我可以看到dropwdown中的值。现在我尝试使用jquery选择特定值，如下所示，但它没有选择值。

$("#MST_CPH_AddAppointment_ddlAptAssociateName").val("MyValue");

如果我在设计时添加值，如上面选择MyValue的代码工作正常。

<asp:DropDownList ID="ddlAptAssociateName" runat="server" CssClass="DropdownList">
            <asp:ListItem>SomeValue</asp:ListItem>
            <asp:ListItem>MyValue</asp:ListItem>
        </asp:DropDownList>

请帮我这样做。

Answer 1

你去了我无法抗拒添加jsDoc：D

/**
 *
 * @param StoreNum
 * @param dropdownid
 * @param {Function} callback
 * @constructor
 */
function GetAssociates( StoreNum, dropdownid, callback ) {
    $.ajax( {
        type       : "POST",
        url        : "Appointment.aspx/BindAssociates",
        data       : "{storeNumber:" + StoreNum + "}",
        contentType: "application/json; charset=utf-8",
        dataType   : "json",
        success    : function ( result ) {
            var rs     = result.d;
            var select = $( "#" + dropdownid );
            //var select = document.getElementById(dropdownid);

            for ( var i = 0; i < rs.length; i++ ) {
                var opt = rs[ i ].trim();
                select.append( new Option( opt, opt ) );
            }
            // apply will run the function with 'this' as first committed argument-> select
            callback.apply( select );
        },
        error      : function ( result ) {
            alert( "Failed to load dropdown" + result );
        }
    } );
}

function load() {
    // GetAssociates is a constructor due to uppercased name
    // my idea will mark this as error -> never mind in your case
    GetAssociates( 1, "MST_CPH_AddAppointment_ddlAptAssociateName", function () {
        this.val( "MyValue" );
    } );
}

Answer 2

您使用.val()错误。您可以通过执行以下操作获得价值：

var myVal =  $("#MST_CPH_AddAppointment_ddlAptAssociateName").val();

您可以通过执行以下操作将值设置为MyValue：

$("#MST_CPH_AddAppointment_ddlAptAssociateName").val("MyValue");

无法使用jquery

2 个答案: