反射讲解

基本反射使用

    [MenuItem("Tools/测试反射")]
    public static void TestReflection()
    {
        TestForReflection test = new TestForReflection();
        test.isTest = true;
        test.Id = 1;
        test.Name = "test";

        object nameValue = null;
        Type testType = test.GetType();

        MemberInfo[] members = testType.GetMember("Name", BindingFlags.Public | BindingFlags.Instance | BindingFlags.Static);//必须要添加BindingFlags.Instance | BindingFlags.Static，BindingFlags都使用位运算

        while (members == null || members.Length == 0)//如果当前Type没有，就从BaseType开始找
        {
            testType = testType.BaseType;
            if (testType == null)
            {
                return;
            }
            members = testType.GetMember("Name",BindingFlags.Public | BindingFlags.Instance | BindingFlags.Static);
        }
        switch (members[0].MemberType)
        {
            case MemberTypes.Field:
                nameValue = testType.GetField("Name", BindingFlags.Public | BindingFlags.Instance | BindingFlags.Static).GetValue(test);
                break;
            case MemberTypes.Property:
                nameValue = testType.GetProperty("Name",BindingFlags.Public | BindingFlags.Instance | BindingFlags.Static).GetValue (test);
                break;
            default: 
                break;
        }
        Debug.Log(nameValue);
    }
public class TestForReflection
{
    public int Id;
    public string Name;
    public bool isTest;
}

反射得到属性和变量的方法封装

将上述反射方法封装一下，再进行调用

[MenuItem("Tools/测试反射")]
public static void TestReflection()
{
    TestForReflection test = new TestForReflection();
    test.isTest = true;
    test.Id = 1;
    test.Name = "test";

    object nameValue = null;
    nameValue = GetMemberValue(test, "Name");
    Debug.Log(nameValue);
}
/// <summary>
/// 反射类里面属性和变量的值
/// </summary>
/// <param name="obj">想要反射的类</param>
/// <param name="memberName">想要反射的属性或变量的名字</param>
/// <param name="bindingAttr">bindingFlags</param>
/// <returns>属性和变量的值</returns>
private static object GetMemberValue(object obj,string memberName, BindingFlags bindingAttr = BindingFlags.Public | BindingFlags.Instance | BindingFlags.Static)
{
    Type testType = obj.GetType();

    MemberInfo[] members = testType.GetMember(memberName, bindingAttr);//必须要添加BindingFlags.Instance | BindingFlags.Static，BindingFlags都使用位运算

    while (members == null || members.Length == 0)//如果当前Type没有，就从BaseType开始找
    {
        testType = testType.BaseType;
        if (testType == null)
        {
            return null;
        }
        members = testType.GetMember(memberName, bindingAttr);
    }
    switch (members[0].MemberType)
    {
        case MemberTypes.Field:
            return testType.GetField(memberName, bindingAttr).GetValue(obj);
        case MemberTypes.Property:
            return testType.GetProperty(memberName, bindingAttr).GetValue(obj);
        default:
            return null;
    }
}

反射list

我们给TestForReflection添加一个List<string>

    [MenuItem("Tools/测试反射")]
    public static void TestReflection()
    {
        TestForReflection test = new TestForReflection();
        test.isTest = true;
        test.Id = 1;
        test.Name = "test";
        test.testList = new List<string>() { "1", "2", "3" };
        
        object list = GetMemberValue(test,"testList");
        int listCount = System.Convert.ToInt32(list.GetType().InvokeMember("get_Count", BindingFlags.Default | BindingFlags.InvokeMethod, null, list, new object[] { }));
        for (int i = 0; i < listCount; i++)
        {
            object item = list.GetType().InvokeMember("get_Item",BindingFlags.Default | BindingFlags.InvokeMethod,null,list, new object[] { i });
            Debug.Log(item);
        }

        //Debug.Log(listCount);
    }

public class TestForReflection
{
    public int Id;
    public string Name;
    public bool isTest;
    public List<string> testList;
}

我们先用list.GetType()得到list的Type，也就是System.Collections.Generic.List1[System.String]`

然后使用InvokeMember方法，反射调用List类的"get_Count"方法，当我们使用InvokeMember方法时，它的参数有：

public object? InvokeMember (string name, System.Reflection.BindingFlags invokeAttr, System.Reflection.Binder? binder, object? target, object?[]? args);

第一个参数就是"get_Count"，第二个参数是BindingFlags.Default | BindingFlags.InvokeMethod，这个也算是固定用法，BindingFlags.InvokeMethod就是配合InvokeMember方法的。第三个参数Binder我们设为null，第四个参数target我们需要传一个有实例的object，因为"get_Count"并不是一个静态方法，如果我们要调用就必须传一个target。第五个参数我们传一个空的数组，一般这个参数数组就是用来传"get_Count"所需要的参数的。

反射自定义class的list

上面的例子我们反射的是List<string>，在实际使用中，我们大多数情况下会反射自定义类。

    [MenuItem("Tools/测试反射")]
    public static void TestReflection()
    {
        TestForReflection test = new TestForReflection();
        test.isTest = true;
        test.Id = 1;
        test.Name = "test";
        test.testList = new List<string>() { "1", "2", "3" };
        test.testList2 = new List<TestForListReflection>
        {
            new TestForListReflection{ Id = 1, Name = "test1" },
            new TestForListReflection{ Id = 2, Name = "test2" },
            new TestForListReflection{ Id = 3, Name = "test3" },
        };

        //object list = GetMemberValue(test,"testList");
        //int listCount = System.Convert.ToInt32(list.GetType().InvokeMember("get_Count", BindingFlags.Default | BindingFlags.InvokeMethod, null, list, new object[] { }));
        //for (int i = 0; i < listCount; i++)
        //{
        //    object item = list.GetType().InvokeMember("get_Item",BindingFlags.Default | BindingFlags.InvokeMethod,null,list, new object[] { i });
        //    Debug.Log(item);
        //}

        object list2 = GetMemberValue(test, "testList2");
        int list2Count = System.Convert.ToInt32(list2.GetType().InvokeMember("get_Count", BindingFlags.Default | BindingFlags.InvokeMethod, null, list2, new object[] { }));
        for (int i = 0; i < list2Count; i++)
        {
            object item = list2.GetType().InvokeMember("get_Item", BindingFlags.Default | BindingFlags.InvokeMethod, null, list2, new object[] { i });
            object id = GetMemberValue(item, "Id");
            object name = GetMemberValue(item, "Name");
            Debug.Log(id + " " +  name);
        }
        //Debug.Log(listCount);
    }
public class TestForReflection
{
    public int Id;
    public string Name;
    public bool isTest;
    public List<string> testList;
    public List<TestForListReflection> testList2;
}
public class TestForListReflection
{
    public int Id { get; set; }
    public string Name { get; set; }
}

通过反射创建实例

封装Activator.CreateInstance

/// <summary>
/// 将类的实例通过反射创建
/// </summary>
/// <param name="name">类名</param>
/// <returns>类的实例</returns>
private static object CreateClassInstance(string name)
{
    object obj = null;
    Type type = null;
    foreach (Assembly asm in AppDomain.CurrentDomain.GetAssemblies())
    {
        Type curType = asm.GetType(name);
        if (curType != null)
        {
            type = curType;
            break;
        }
    }
    if(type !=  null)
    {
        obj = Activator.CreateInstance(type);
    }
    return obj;
}

通过反射创建实例并赋值

    [MenuItem("Tools/测试反射创建")]
    public static void TestReflection2()
    {
        object obj = CreateClassInstance("TestForReflection");

        PropertyInfo idInfo = obj.GetType().GetProperty("Id");
        idInfo.SetValue(obj, Convert.ToInt32("11"));
        PropertyInfo nameInfo = obj.GetType().GetProperty("Name");
        nameInfo.SetValue(obj,"ATAO");
        PropertyInfo boolInfo = obj.GetType().GetProperty("isTest");
        boolInfo.SetValue(obj, Convert.ToBoolean("true"));
        PropertyInfo floatInfo = obj.GetType().GetProperty("Height");
        floatInfo.SetValue(obj, Convert.ToSingle("12.5"));
        PropertyInfo enumInfo = obj.GetType().GetProperty("TestEn");
        object enumValue = TypeDescriptor.GetConverter(enumInfo.PropertyType).ConvertFromInvariantString("Test1");
        enumInfo.SetValue(obj, enumValue);

        TestForReflection test = obj as TestForReflection;
        Debug.Log(test.Id + " " + test.Name + " " + test.isTest + " " + test.Height + " " + test.TestEn);
    }


public class TestForReflection
{
    public int Id { get; set; }
    public string Name { get; set; }
    public bool isTest { get; set; }
    public float Height { get; set; }
    public TestEnum TestEn { get; set; }
    //public List<string> testList;
   // public List<TestForListReflection> testList2;
}
public enum TestEnum
{
    None = 0,
    Test1 = 1,
    Test2 = 2,
}

注意Enum的转换方式：使用TypeDescriptor.GetConverter得到Enum的转换器，然后调用ConvertFromInvariantString

只有这样我们才能调用PropertyInfo.SetValue来设置枚举的值

封装SetValue方法

[MenuItem("Tools/测试反射创建")]
public static void TestReflection2()
{
    object obj = CreateClassInstance("TestForReflection");

    PropertyInfo idInfo = obj.GetType().GetProperty("Id");
    SetValue(idInfo, obj, "11", "int");
    PropertyInfo nameInfo = obj.GetType().GetProperty("Name");
    SetValue(nameInfo, obj, "ATAO", "string");
    PropertyInfo boolInfo = obj.GetType().GetProperty("isTest");
    SetValue(boolInfo, obj, "true", "bool");
    PropertyInfo floatInfo = obj.GetType().GetProperty("Height");
    SetValue(floatInfo, obj, "12.3", "float");
    PropertyInfo enumInfo = obj.GetType().GetProperty("TestEn");
    SetValue(enumInfo, obj, "Test2", "enum");

    TestForReflection test = obj as TestForReflection;
    Debug.Log(test.Id + " " + test.Name + " " + test.isTest + " " + test.Height + " " + test.TestEn);
}
/// <summary>
/// 将反射的属性进行赋值
/// </summary>
/// <param name="info">反射的属性</param>
/// <param name="var">此属性所在的obj</param>
/// <param name="value">赋值</param>
/// <param name="type">类型</param>
private static void SetValue(PropertyInfo info, object var, string value,string type)
{
    object val = (object)value;

    switch (type)
    {
        case "int":
            val = Convert.ToInt32(val);
            break;
        case "float":
            val = Convert.ToSingle(val);
            break;
        case "bool":
            val = Convert.ToBoolean(val);
            break;
        case "enum":
            val = TypeDescriptor.GetConverter(info.PropertyType).ConvertFromInvariantString(val.ToString());
            break;
    }
    info.SetValue(var, val);
}

通过反射创建List

通过反射创建普通List

    [MenuItem("Tools/测试反射创建")]
    public static void TestReflection2()
    {
        object obj = CreateClassInstance("TestForReflection");

        //...
        Type stringType = typeof(string);
        Type listType = typeof(List<>);
        Type listGenericType = listType.MakeGenericType(new System.Type[] { stringType });
        object listObj = Activator.CreateInstance(listGenericType,new object[] {});//需要参数

        for (int i = 0; i < 3; i++)
        {
            string itemStr = "TestList" + i;
            listObj.GetType().InvokeMember("Add",BindingFlags.Default | BindingFlags.InvokeMethod,null,listObj,new object[] {itemStr});
        }

        obj.GetType().GetField("testList").SetValue(obj, listObj);

        TestForReflection test = obj as TestForReflection;
        //...
        test.testList.ForEach(x => { Debug.Log(x); });
    }


public class TestForReflection
{
    public int Id { get; set; }
    public string Name { get; set; }
    public bool isTest { get; set; }
    public float Height { get; set; }
    public TestEnum TestEn { get; set; }
    public List<string> testList { get; set; }
    public List<TestForListReflection> testList2 { get;set; }
}

注意看创建时使用的API

封装创建泛型ListType的方法

/// <summary>
/// 创建泛型ListType
/// </summary>
/// <param name="type">泛型类型</param>
/// <returns></returns>
private static object CreateListGenericType(Type type)
{
    Type listGenericType = typeof(List<>).MakeGenericType(new System.Type[] {type});
    return Activator.CreateInstance(listGenericType,new object[] {});
}

通过反射创建自定义类List

[MenuItem("Tools/测试反射创建")]
public static void TestReflection2()
{
    object obj = CreateClassInstance("TestForReflection");

    //...
    

    object testListObj = CreateListGenericType(typeof(TestForListReflection));
    for (int i = 0; i < 3; i++)
    {
        object testIns = CreateClassInstance("TestForListReflection");
        PropertyInfo testIdInfo = testIns.GetType().GetProperty("Id");
        SetValue(testIdInfo, testIns, i.ToString(), "int");
        PropertyInfo testNameInfo = testIns.GetType().GetProperty("Name");
        SetValue(testNameInfo, testIns, i.ToString() + "Test","string");
        testListObj.GetType().InvokeMember("Add",BindingFlags.Default | BindingFlags.InvokeMethod,null,testListObj,new object[] {testIns});
    }

    obj.GetType().GetProperty("testList2").SetValue (obj, testListObj);

    TestForReflection test = obj as TestForReflection;
    //...
    test.testList2.ForEach(x => { Debug.Log(x.Id + " " + x.Name); });
}