1.使用ViewData
ViewData 的是ControllerBase 的一个属性,是一个数据字典类型的，其实现代码如(这段代码来自asp.net MVC开源项目中源码)下:
Code
1 public class ViewDataDictionary : IDictionary<string, object> {
2
3 private readonly Dictionary<string, object> _innerDictionary = new Dictionary<string, object>(StringComparer.OrdinalIgnoreCase);
4 private object _model;
5 private readonly ModelStateDictionary _modelState = new ModelStateDictionary();
6
7 public ViewDataDictionary()
8 : this((object)null) {
9 }
10
11 [SuppressMessage("Microsoft.Usage", "CA2214:DoNotCallOverridableMethodsInConstructors",
12 Justification = "See note on SetModel() method.")]
13 public ViewDataDictionary(object model) {
14 Model = model;
15 }
16
17 [SuppressMessage("Microsoft.Usage", "CA2214:DoNotCallOverridableMethodsInConstructors",
18 Justification = "See note on SetModel() method.")]
19 public ViewDataDictionary(ViewDataDictionary dictionary) {
20 if (dictionary == null) {
21 throw new ArgumentNullException("dictionary");
22 }
23
24 foreach (var entry in dictionary) {
25 _innerDictionary.Add(entry.Key, entry.Value);
26 }
27 foreach (var entry in dictionary.ModelState) {
28 ModelState.Add(entry.Key, entry.Value);
29 }
30 Model = dictionary.Model;
31 }
32
33 [SuppressMessage("Microsoft.Security", "CA2123:OverrideLinkDemandsShouldBeIdenticalToBase")]
34 public int Count {
35 get {
36 return _innerDictionary.Count;
37 }
38 }
39
40 [SuppressMessage("Microsoft.Security", "CA2123:OverrideLinkDemandsShouldBeIdenticalToBase")]
41 public bool IsReadOnly {
42 get {
43 return ((IDictionary<string, object>)_innerDictionary).IsReadOnly;
44 }
45 }
46
47 [SuppressMessage("Microsoft.Security", "CA2123:OverrideLinkDemandsShouldBeIdenticalToBase")]
48 public ICollection<string> Keys {
49 get {
50 return _innerDictionary.Keys;
51 }
52 }
53
54 public object Model {
55 get {
56 return _model;
57 }
58 set {
59 SetModel(value);
60 }
61 }
62
63 public ModelStateDictionary ModelState {
64 get {
65 return _modelState;
66 }
67 }
68
69 [SuppressMessage("Microsoft.Security", "CA2123:OverrideLinkDemandsShouldBeIdenticalToBase")]
70 public object this[string key] {
71 get {
72 object value;
73 _innerDictionary.TryGetValue(key, out value);
74 return value;
75 }
76 set {
77 _innerDictionary[key] = value;
78 }
79 }
80
81 [SuppressMessage("Microsoft.Security", "CA2123:OverrideLinkDemandsShouldBeIdenticalToBase")]
82 public ICollection<object> Values {
83 get {
84 return _innerDictionary.Values;
85 }
86 }
87
88 [SuppressMessage("Microsoft.Security", "CA2123:OverrideLinkDemandsShouldBeIdenticalToBase")]
89 public void Add(KeyValuePair<string, object> item) {
90 ((IDictionary<string, object>)_innerDictionary).Add(item);
91 }
92
93 [SuppressMessage("Microsoft.Security", "CA2123:OverrideLinkDemandsShouldBeIdenticalToBase")]
94 public void Add(string key, object value) {
95 _innerDictionary.Add(key, value);
96 }
97
98 [SuppressMessage("Microsoft.Security", "CA2123:OverrideLinkDemandsShouldBeIdenticalToBase")]
99 public void Clear() {
100 _innerDictionary.Clear();
101 }
102
103 [SuppressMessage("Microsoft.Security", "CA2123:OverrideLinkDemandsShouldBeIdenticalToBase")]
104 public bool Contains(KeyValuePair<string, object> item) {
105 return ((IDictionary<string, object>)_innerDictionary).Contains(item);
106 }
107
108 [SuppressMessage("Microsoft.Security", "CA2123:OverrideLinkDemandsShouldBeIdenticalToBase")]
109 public bool ContainsKey(string key) {
110 return _innerDictionary.ContainsKey(key);
111 }
112
113 [SuppressMessage("Microsoft.Security", "CA2123:OverrideLinkDemandsShouldBeIdenticalToBase")]
114 public void CopyTo(KeyValuePair<string, object>[] array, int arrayIndex) {
115 ((IDictionary<string, object>)_innerDictionary).CopyTo(array, arrayIndex);
116 }
117
118 [SuppressMessage("Microsoft.Naming", "CA1704:IdentifiersShouldBeSpelledCorrectly", MessageId = "Eval",
119 Justification = "Commonly used shorthand for Evaluate.")]
120 public object Eval(string expression) {
121 if (String.IsNullOrEmpty(expression)) {
122 throw new ArgumentException(MvcResources.Common_NullOrEmpty, "expression");
123 }
124
125 return ViewDataEvaluator.Eval(this, expression);
126 }
127
128 [SuppressMessage("Microsoft.Naming", "CA1704:IdentifiersShouldBeSpelledCorrectly", MessageId = "Eval",
129 Justification = "Commonly used shorthand for Evaluate.")]
130 public string Eval(string expression, string format) {
131 object value = Eval(expression);
132
133 if (value == null) {
134 return String.Empty;
135 }
136
137 if (String.IsNullOrEmpty(format)) {
138 return Convert.ToString(value, CultureInfo.CurrentCulture);
139 }
140 else {
141 return String.Format(CultureInfo.CurrentCulture, format, value);
142 }
143 }
144
145 [SuppressMessage("Microsoft.Security", "CA2123:OverrideLinkDemandsShouldBeIdenticalToBase")]
146 public IEnumerator<KeyValuePair<string, object>> GetEnumerator() {
147 return _innerDictionary.GetEnumerator();
148 }
149
150 [SuppressMessage("Microsoft.Security", "CA2123:OverrideLinkDemandsShouldBeIdenticalToBase")]
151 public bool Remove(KeyValuePair<string, object> item) {
152 return ((IDictionary<string, object>)_innerDictionary).Remove(item);
153 }
154
155 [SuppressMessage("Microsoft.Security", "CA2123:OverrideLinkDemandsShouldBeIdenticalToBase")]
156 public bool Remove(string key) {
157 return _innerDictionary.Remove(key);
158 }
159
160 // This method will execute before the derived type's instance constructor executes. Derived types must
161 // be aware of this and should plan accordingly. For example, the logic in SetModel() should be simple
162 // enough so as not to depend on the "this" pointer referencing a fully constructed object.
163 protected virtual void SetModel(object value) {
164 _model = value;
165 }
166
167 [SuppressMessage("Microsoft.Security", "CA2123:OverrideLinkDemandsShouldBeIdenticalToBase")]
168 public bool TryGetValue(string key, out object value) {
169 return _innerDictionary.TryGetValue(key, out value);
170 }
171
172 internal static class ViewDataEvaluator {
173 public static object Eval(ViewDataDictionary vdd, string expression) {
174 //Given an expression "foo.bar.baz" we look up the following (pseudocode):
175 // this["foo.bar.baz.quux"]
176 // this["foo.bar.baz"]["quux"]
177 // this["foo.bar"]["baz.quux]
178 // this["foo.bar"]["baz"]["quux"]
179 // this["foo"]["bar.baz.quux"]
180 // this["foo"]["bar.baz"]["quux"]
181 // this["foo"]["bar"]["baz.quux"]
182 // this["foo"]["bar"]["baz"]["quux"]
183
184 object evaluated = EvalComplexExpression(vdd, expression);
185 return evaluated;
186 }
187
188 private static object EvalComplexExpression(object indexableObject, string expression) {
189 foreach (ExpressionPair expressionPair in GetRightToLeftExpressions(expression)) {
190 string subExpression = expressionPair.Left;
191 string postExpression = expressionPair.Right;
192
193 object subtarget = GetPropertyValue(indexableObject, subExpression);
194 if (subtarget != null) {
195 if (String.IsNullOrEmpty(postExpression))
196 return subtarget;
197
198 object potential = EvalComplexExpression(subtarget, postExpression);
199 if (potential != null) {
200 return potential;
201 }
202 }
203 }
204 return null;
205 }
206
207 private static IEnumerable<ExpressionPair> GetRightToLeftExpressions(string expression) {
208 // Produces an enumeration of all the combinations of complex property names
209 // given a complex expression. See the list above for an example of the result
210 // of the enumeration.
211
212 yield return new ExpressionPair(expression, String.Empty);
213
214 int lastDot = expression.LastIndexOf('.');
215
216 string subExpression = expression;
217 string postExpression = string.Empty;
218
219 while (lastDot > -1) {
220 subExpression = expression.Substring(0, lastDot);
221 postExpression = expression.Substring(lastDot + 1);
222 yield return new ExpressionPair(subExpression, postExpression);
223
224 lastDot = subExpression.LastIndexOf('.');
225 }
226 }
227
228 private static object GetIndexedPropertyValue(object indexableObject, string key) {
229 Type indexableType = indexableObject.GetType();
230
231 ViewDataDictionary vdd = indexableObject as ViewDataDictionary;
232 if (vdd != null) {
233 return vdd[key];
234 }
235
236 MethodInfo containsKeyMethod = indexableType.GetMethod("ContainsKey", BindingFlags.Public | BindingFlags.Instance, null, new Type[] { typeof(string) }, null);
237 if (containsKeyMethod != null) {
238 if (!(bool)containsKeyMethod.Invoke(indexableObject, new object[] { key })) {
239 return null;
240 }
241 }
242
243 PropertyInfo info = indexableType.GetProperty("Item", BindingFlags.Public | BindingFlags.Instance, null, null, new Type[] { typeof(string) }, null);
244 if (info != null) {
245 return info.GetValue(indexableObject, new object[] { key });
246 }
247
248 PropertyInfo objectInfo = indexableType.GetProperty("Item", BindingFlags.Public | BindingFlags.Instance, null, null, new Type[] { typeof(object) }, null);
249 if (objectInfo != null) {
250 return objectInfo.GetValue(indexableObject, new object[] { key });
251 }
252 return null;
253 }
254
255 private static object GetPropertyValue(object container, string propertyName) {
256 // This method handles one "segment" of a complex property expression
257
258 // First, we try to evaluate the property based on its indexer
259 object value = GetIndexedPropertyValue(container, propertyName);
260 if (value != null) {
261 return value;
262 }
263
264 // If the indexer didn't return anything useful, continue
265
266 // If the container is a ViewDataDictionary then treat its Model property
267 // as the container instead of the ViewDataDictionary itself.
268 ViewDataDictionary vdd = container as ViewDataDictionary;
269 if (vdd != null) {
270 container = vdd.Model;
271 }
272
273 // Second, we try to use PropertyDescriptors and treat the expression as a property name
274 PropertyDescriptor descriptor = TypeDescriptor.GetProperties(container).Find(propertyName, true);
275 if (descriptor == null) {
276 return null;
277 }
278
279 return descriptor.GetValue(container);
280 }
281
282 private struct ExpressionPair {
283 public readonly string Left;
284 public readonly string Right;
285
286 public ExpressionPair(string left, string right) {
287 Left = left;
288 Right = right;
289 }
290 }
291 }
292
293 #region IEnumerable Members
294 [SuppressMessage("Microsoft.Security", "CA2123:OverrideLinkDemandsShouldBeIdenticalToBase")]
295 IEnumerator IEnumerable.GetEnumerator() {
296 return ((IEnumerable)_innerDictionary).GetEnumerator();
297 }
298 #endregion
299
300 }
ViewData的用法如下:ViewData["user"] = LoginUser; 页面的代码<%=(ViewData["user"] as Users).UserName%>
ViewData的作用域从控制器设置值到页面值显示。
2.使用TempData
TempData同样属于ControllerBase 的属性 用法和ViewData 基本相同，但是他们的实质是不同的，ViewData 是数据字典类型而TempData是Session存储的值，TempData数据只能在控制器中传递一次，每个元素也只能被访问一次，然后Session中的值就会被自动删除，它的生命周期要比ViewData的要长.
3.使用Model
使用Model 顾名思义就是将一个实体对象绑定在页面上，上面两种都是放在作用域中。这里只讲用法。
public ActionResult Student()
{
DbContext context=new DbContext();
Student stu=context.Single(s=>s.ID==1);
return View(stu);
}
页面代码的使用：<%=(Model as MVCTest.Models.Student).Name %> Model 是ViewPage d的一个属性值，用于 接收控制器中返回的值
Model 传输数据还可以这样用：
<%@ Page Language="C#" Inherits="System.Web.Mvc.ViewPage<MVCTest.Models.Student>" %>
<%=Model.Name %>
使用泛型的ViewPage，将Model中的值指定特定类型不用强制性转换
4.传递多个对象类型
其实传递多个对象类型，最简单的办法就是将这些对象封装成另外一个类的属性，然后将这个对象传递到页面。不在做介绍