MVC地区多级联动扩展实现(非递归形式)
MVC前台界面调用方式如下:
@Html.AreaDropDownList("areaCode", areaCode, 3, string.Empty)
参数说明:
第一个参数控件的名称;
第二个参数选中的地区编码;
第三个参数地区层级;
第四个参数根级地区;
地区数据库表设计如下:
下拉列表的扩展:
![](https://images.cnblogs.com/OutliningIndicators/ContractedBlock.gif)
1 #region 下拉列表 2 3 /// <summary> 4 /// 联动下拉列表 5 /// </summary> 6 /// <param name="htmlHelper">被扩展的HtmlHelper实例</param> 7 /// <param name="expression">获取数据集合</param> 8 /// <param name="level">显示多少级</param> 9 /// <param name="defaultValue">TProperty类型的默认值(如string默认值为"")</param> 10 /// <param name="rootItems">获取根级列表数据</param> 11 /// <param name="getParentID">获取列表项的ParentID方法</param> 12 /// <param name="getChildItems">获取子级列表数据集合方法</param> 13 /// <param name="getChildSelectDataUrl">获取子级列表数据的远程地址</param> 14 /// <returns>html代码</returns> 15 public static MvcHtmlString LinkageDropDownListFor<TModel, TProperty>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, TProperty>> expression, TProperty defaultValue, int level, Dictionary<TProperty, string> rootItems,Func<TProperty, TProperty> getParentID, Func<TProperty, Dictionary<TProperty, string>> getChildItems,string getChildSelectDataUrl,string optionLabel = "请选择") 16 { 17 ModelMetadata metadata = ModelMetadata.FromLambdaExpression(expression, htmlHelper.ViewData); 18 19 return LinkageDropDownList(htmlHelper, ExpressionHelper.GetExpressionText(expression), (TProperty)metadata.Model, defaultValue, level, rootItems, getParentID,getChildItems,getChildSelectDataUrl,optionLabel); 20 } 21 22 23 /// <summary> 24 /// 联动下拉列表 25 /// </summary> 26 /// <param name="htmlHelper">被扩展的HtmlHelper实例</param> 27 /// <param name="level">显示多少级</param> 28 /// <param name="defaultValue">TProperty类型的默认值(如string默认值为"")</param> 29 /// <param name="name">下拉列表表单项名</param> 30 /// <param name="selectedValue">当前选中值</param> 31 /// <param name="rootItems">获取根级列表数据</param> 32 /// <param name="getParentId">获取列表项的ParentID方法</param> 33 /// <param name="getChildItems">获取子级列表数据集合方法</param> 34 /// <param name="getChildSelectDataUrl">获取子级列表数据的远程地址</param> 35 /// <returns>html代码</returns> 36 public static MvcHtmlString LinkageDropDownList<TProperty>(this HtmlHelper htmlHelper, string name, TProperty selectedValue,TProperty defaultValue, int level, Dictionary<TProperty, string> rootItems, Func<TProperty, TProperty> getParentId, Func<TProperty, Dictionary<TProperty, string>> getChildItems, string getChildSelectDataUrl, string optionLabel = "请选择") 37 { 38 string fullName = htmlHelper.ViewContext.ViewData.TemplateInfo.GetFullHtmlFieldName(name); 39 //select data init 40 Stack<Dictionary<TProperty, string>> stack = new Stack<Dictionary<TProperty, string>>(); 41 42 //如果有选中的值,则查找其所在列表前面的所有列表 43 IList<TProperty> selectedValues = new List<TProperty>(); 44 if (selectedValue != null && !selectedValue.Equals(defaultValue)) 45 { 46 TProperty itemId = selectedValue; 47 TProperty parentItemId = getParentId(itemId); 48 while (!itemId.Equals(defaultValue) && !parentItemId.Equals(defaultValue)) 49 { 50 stack.Push(getChildItems(parentItemId)); 51 selectedValues.Add(itemId); 52 itemId = parentItemId; 53 parentItemId = getParentId(itemId); 54 } 55 if (rootItems.Count() > 0) 56 { 57 TProperty rootId = getParentId(rootItems.First().Key); 58 if (!itemId.Equals(rootId)) 59 { 60 stack.Push(rootItems); 61 selectedValues.Add(itemId); 62 } 63 } 64 } 65 else 66 { 67 TProperty rootItemID = rootItems.Select(n => n.Key).FirstOrDefault(); 68 stack.Push(rootItems); 69 } 70 71 //生成标签 72 TagBuilder containerBuilder = new TagBuilder("span"); 73 containerBuilder.MergeAttribute("plugin", "linkageDropDownList"); 74 var data = new Dictionary<string, object>(); 75 data.TryAdd("GetChildSelectDataUrl", getChildSelectDataUrl); 76 data.TryAdd("ControlName", name); 77 data.TryAdd("Level", level); 78 data.TryAdd("OptionLabel", optionLabel); 79 data.TryAdd("DefaultValue", defaultValue.ToString()); 80 containerBuilder.MergeAttribute("data", Json.Encode(data)); 81 int currentIndex = 0; 82 while (stack.Count > 0) 83 { 84 Dictionary<TProperty, string> dictionary = stack.Pop(); 85 IEnumerable<SelectListItem> selectList = dictionary.Select(n => new SelectListItem() { Selected = selectedValues.Contains(n.Key), Text = n.Value, Value = n.Key.ToString() }); 86 containerBuilder.InnerHtml += "\r\n" + htmlHelper.DropDownList(string.Format("{0}_{1}", name, currentIndex), selectList, 87 optionLabel, new { @class = "tn-dropdownlist" }); 88 currentIndex++; 89 } 90 containerBuilder.InnerHtml += "\r\n" + htmlHelper.Hidden(name); 91 return MvcHtmlString.Create(containerBuilder.ToString()); 92 } 93 94 #endregion
对外的调用的实现:
1 /// <summary> 2 /// 地区下拉列表 3 /// </summary> 4 /// <param name="htmlHelper">被扩展的htmlHelper实例</param> 5 /// <param name="expression">选择实体中类别属性的lamda表达式</param> 6 /// <param name="areaLevel">地区层级(默认取站点地区配置)</param> 7 /// <param name="rootAreaCode">根级地区(默认取站点地区配置)</param> 8 public static MvcHtmlString AreaDropDownListFor<TModel>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, string>> expression, int? areaLevel = null, string rootAreaCode = null) 11 { 12 string getChildAreasUrl = "/Channel/GetChildAreas";//获取子地区的远程地址,(AreaCode,name)的JSON数据 13 if (areaLevel == null) 15 { 16 areaLevel = 0;//区域设置级别,可以作为配置文件获取 17 } 18 return htmlHelper.LinkageDropDownListFor<TModel, string>(expression, string.Empty, areaLevel.Value, 获取根级区域的(AreaCode,name)键值对,获取当前选中区域的父区域, 获取当前的子区域, getChildAreasUrl); 21 } 22 23 /// <summary> 24 /// 地区下拉列表 25 /// </summary> 26 /// <param name="htmlHelper">被扩展的htmlHelper实例</param> 27 /// <param name="name">控件name属性</param> 28 /// <param name="name">选中的地区编码</param> 29 /// <param name="areaLevel">地区层级(默认取站点配置)</param> 30 /// <param name="rootAreaCode">根级地区(默认取站点地区配置)</param> 31 public static MvcHtmlString AreaDropDownList(this HtmlHelper htmlHelper, string name, string value, int? areaLevel = null, string rootAreaCode = null) 32 { 33 string getChildAreasUrl = "/Channel/GetChildAreas";//获取子地区的远程地址,(AreaCode,name)的JSON数据 34 if (areaLevel == null) 36 { 37 areaLevel = 0;//区域设置级别,可以作为配置文件获取 38 } 39 return htmlHelper.LinkageDropDownList<string>(name, value, string.Empty, areaLevel.Value, 获取根级区域的(AreaCode,name)键值对, 获取当前选中区域的父区域, 获取选中地区当前的子区域, getChildAreasUrl); 42 }