下面是一个可能的替代代码，它可能更适合您的场景：

var province = $("select[name='@(Model.ProvinceFieldName)']");
var provinceValue = '@provinceId';
var city = $("select[name='@(Model.CityFieldName)']");
var center = $("select[name='@(Model.CenterFieldName)']");
var centerType = $("select[name='@(Model.CenterTypeFieldName)']");
var region = $("select[name='@(Model.RegionFieldName)']");

if (provinceValue) {
    // Set the value of province combobox and trigger change event
    province.val(provinceValue).trigger('change');
    // Attach a change event handler to province combobox
    province.change(function () {
        // Get the selected value of province combobox
        var provinceId = $(this).val();
        // Check if provinceId is valid
        if (provinceId) {
            // Populate region combobox based on provinceId
            $.getJSON("/Admin/GetRegionList/", { provinceId: provinceId }, function (result) {
                // Clear the options of region combobox
                region.empty();
                // Loop through each item in result
                $.each(result, function (index, item) {
                    // Create a new option element with value and text from item
                    var option = $("<option></option>").val(item.RegionID).text(item.Name);
                    // Append the option element to region combobox
                    region.append(option);
                });
                // Set the value of region combobox based on region name and trigger change event
                region.val('@regionId').trigger('change');
            });
        }
    });
    // Attach a change event handler to region combobox
    region.change(function () {
        // Get the selected value of region combobox
        var regionId = $(this).val();
        // Check if regionId is valid
        if (regionId) {
            // Populate city combobox based on regionId
            $.getJSON("/Admin/GetCityList/", { regionId: regionId }, function (result) {
                // Clear the options of city combobox
                city.empty();
                // Loop through each item in result
                $.each(result, function (index, item) {
                    // Create a new option element with value and text from item
                    var option = $("<option></option>").val(item.CityID).text(item.Name);
                    // Append the option element to city combobox
                    city.append(option);
                });
                // Set the value of city combobox based on city id and trigger change event
                city.val('@cityId').trigger('change');
            });
        }
    });
    // Attach a change event handler to city combobox
    city.change(function () {
        // Get the selected value of city combobox
        var cityId = $(this).val();
        // Check if cityId is valid
        if (cityId) {
            // Populate center type combobox based on cityId
            $.getJSON("/Admin/GetCenterTypeList/", { cityId: cityId }, function (result) {
                // Clear the options of center type combobox
                centerType.empty();
                // Loop through each item in result
                $.each(result, function (index, item) {
                    // Create a new option element with value and text from item
                    var option = $("<option></option>").val(item.CenterTypeID).text(item.Name);
                    // Append the option element to center type combobox
                    centerType.append(option);
                });
                // Set the value of center type combobox based on center type id and trigger change event
                centerType.val('@centerTypeId').trigger('change');
            });
        }
    });
    // Attach a change event handler to center type combobox
    centerType.change(function () {
        // Get the selected value of center type combobox
        var centerTypeId = $(this).val();
        // Check if centerTypeId is valid
        if (centerTypeId) {
            // Populate center combobox based on centerTypeId
            $.getJSON("/Admin/GetCenterList/", { centerTypeId: centerTypeId }, function (result) {
                // Clear the options of center combobox
                center.empty();
                // Loop through each item in result
                $.each(result, function (index, item) {
                    // Create a new option element with value and text from item
                    var option = $("<option></option>").val(item.CenterID).text(item.Name);
                    // Append the option element to center combobox
                    center.append(option);
                });
                // Set the value of center combobox based on center id and trigger change event
                center.val('@centerId').trigger('change');
            });
        }
    });
}

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