第4篇：Xilium CefGlue 关于 CLR Object 与 JS 交互类库封装报告：委托回调方法分析
本文转自“吾乐吧软件站”，原文链接：http://www.wuleba.com/?p=23620
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开发语言为：.NET/C++ 方向
2、第二种方法，委托回调方法分析
2.1 实现过程：
(1)、定义一个DemoRenderProcessHandler，继承自CefRenderProcessHandler
(2)、重写DemoRenderProcessHandler里的OnWebKitInitialized ( )事件
(3)、定义一个ExampleAv8Handler，继承自CefV8Handler
(4)、在ExampleAv8Handler里的Execute ( )事件中，写你要执行的操作代码
(5)、在Execute ( )事件中，利用委托进行回调，把要操作的代码回调执行
(6)、在OnWebKitInitialized ( )事件里面new ExampleAv8Handler ( )，根据类的实际情况，人工手写JS脚本代码，通过官方提供的RegisterExtension(string extensionName, string javascriptCode, CefV8Handler handler)方法进行注册
(7)、写一个网页，去前台通过JS调用
2.2 核心代码：
/// <summary>
/// DemoRenderProcessHandler.cs
/// </summary>
#region 声明委托回调
/// <summary>
/// 网页脚本与后台程序交互方法
/// 提示一：V8HandlerDelegate要在namespace下面定义，不要写到class里去了
/// 提示二：如果 returnValue = null; 则会导致网页前端出现错误：Cannot read property ’constructor’ of undefined
/// 提示三：还存在其他的可能，导致导致网页前端出现错误：Cannot read property ’constructor’ of undefined
/// </summary>
/// <param name=”name”>名称</param>
/// <param name=”obj”>对象</param>
/// <param name=”arguments”>参数</param>
/// <param name=”returnValue”>返回值</param>
/// <param name=”exception”>返回异常信息</param>
/// <returns></returns>
public delegate void V8HandlerDelegate(string name, CefV8Value obj, CefV8Value[] arguments, out CefV8Value returnValue, out string exception);
#endregion 声明委托回调
#region 声明常量变量
/// <summary>
/// 绑定测试处理器B
/// </summary>
private ExampleBv8Handler exampleB;
/// <summary>
/// 委托回调
/// </summary>
public V8HandlerDelegate CallBack { get; set; }
#endregion 声明常量变量
protected override void OnWebKitInitialized()
{
#region 回调方式注册 ExampleB
exampleB = new ExampleBv8Handler { CallBack = CallBackMethod };
const string exampleBJavascriptCode = @”function exampleB() {}
if (!exampleB) exampleB = {};
(function() {
exampleB.__defineGetter__(‘myProperty’,
function() {
native function MyProperty();
return MyProperty();
});
exampleB.__defineGetter__(‘myReadOnlyProperty’,
function() {
native function MyReadOnlyProperty();
return MyReadOnlyProperty();
});
exampleB.__defineGetter__(‘myUnconvertibleProperty’,
function() {
native function MyUnconvertibleProperty();
return MyUnconvertibleProperty();
});
exampleB.repeat = function(str,n) {
native function Repeat(str,n);
return Repeat(str,n);
};
exampleB.echoVoid = function() {
native function EchoVoid();
EchoVoid();
};
exampleB.echoBoolean = function(arg0) {
native function EchoBoolean(arg0);
return EchoBoolean(arg0);
};
exampleB.echoNullableBoolean = function(arg0) {
native function EchoNullableBoolean(arg0);
return EchoNullableBoolean(arg0);
};
exampleB.echoSByte = function(arg0) {
native function EchoSByte(arg0);
return EchoSByte(arg0);
};
exampleB.echoNullableSByte = function(arg0) {
native function EchoNullableSByte(arg0);
return EchoNullableSByte(arg0);
};
exampleB.echoInt16 = function(arg0) {
native function EchoInt16(arg0);
return EchoInt16(arg0);
};
exampleB.echoNullableInt16 = function(arg0) {
native function EchoNullableInt16(arg0);
return EchoNullableInt16(arg0);
};
exampleB.echoInt32 = function(arg0) {
native function EchoInt32(arg0);
return EchoInt32(arg0);
};
exampleB.echoNullableInt32 = function(arg0) {
native function EchoNullableInt32(arg0);
return EchoNullableInt32(arg0);
};
exampleB.echoInt64 = function(arg0) {
native function EchoInt64(arg0);
return EchoInt64(arg0);
};
exampleB.echoNullableInt64 = function(arg0) {
native function EchoNullableInt64(arg0);
return EchoNullableInt64(arg0);
};
exampleB.echoByte = function(arg0) {
native function EchoByte(arg0);
return EchoByte(arg0);
};
exampleB.echoNullableByte = function(arg0) {
native function EchoNullableByte(arg0);
return EchoNullableByte(arg0);
};
exampleB.echoUInt16 = function(arg0) {
native function EchoUInt16(arg0);
return EchoUInt16(arg0);
};
exampleB.echoUInt32 = function(arg0) {
native function EchoUInt32(arg0);
return EchoUInt32(arg0);
};
exampleB.echoNullableUInt32 = function(arg0) {
native function EchoNullableUInt32(arg0);
return EchoNullableUInt32(arg0);
};
exampleB.echoUInt64 = function(arg0) {
native function EchoUInt64(arg0);
return EchoUInt64(arg0);
};
exampleB.echoNullableUInt64 = function(arg0) {
native function EchoNullableUInt64(arg0);
return EchoNullableUInt64(arg0);
};
exampleB.echoSingle = function(arg0) {
native function EchoSingle(arg0);
return EchoSingle(arg0);
};
exampleB.echoNullableSingle = function(arg0) {
native function EchoNullableSingle(arg0);
return EchoNullableSingle(arg0);
};
exampleB.echoDouble = function(arg0) {
native function EchoDouble(arg0);
return EchoDouble(arg0);
};
exampleB.echoNullableDouble = function(arg0) {
native function EchoNullableDouble(arg0);
return EchoNullableDouble(arg0);
};
exampleB.echoChar = function(arg0) {
native function EchoChar(arg0);
return EchoChar(arg0);
};
exampleB.echoNullableChar = function(arg0) {
native function EchoNullableChar(arg0);
return EchoNullableChar(arg0);
};
exampleB.echoDateTime = function(arg0) {
native function EchoDateTime(arg0);
return EchoDateTime(arg0);
};
exampleB.echoNullableDateTime = function(arg0) {
native function EchoNullableDateTime(arg0);
return EchoNullableDateTime(arg0);
};
exampleB.echoDecimal = function(arg0) {
native function EchoDecimal(arg0);
return EchoDecimal(arg0);
};
exampleB.echoNullableDecimal = function(arg0) {
native function EchoNullableDecimal(arg0);
return EchoNullableDecimal(arg0);
};
exampleB.echoString = function(arg0) {
native function EchoString(arg0);
return EchoString(arg0);
};
exampleB.lowercaseMethod = function(arg0) {
native function LowercaseMethod(arg0);
return LowercaseMethod(arg0);
};
})();”;
CefRuntime.RegisterExtension(“exampleBExtensionName”, exampleBJavascriptCode, exampleB);
#endregion 回调方式注册 ExampleB
base.OnWebKitInitialized();
}
#region 方法
/// <summary>
/// 利用委托回调方法
/// 注意：如果 returnValue = null; 则会导致网页前端出现错误：Cannot read property ’constructor’ of undefined
/// </summary>
/// <param name=”name”></param>
/// <param name=”obj”></param>
/// <param name=”arguments”></param>
/// <param name=”returnValue”></param>
/// <param name=”exception”></param>
public void CallBackMethod(string name, CefV8Value obj, CefV8Value[] arguments, out CefV8Value returnValue, out string exception)
{
returnValue = CefV8Value.CreateString(string.Empty);
exception = null;
}
#endregion 方法
/// <summary>
/// ExampleBv8Handler.cs
/// </summary>
/// <summary>
/// 绑定测试处理器
/// </summary>
public class ExampleBv8Handler : CefV8Handler
{
#region 声明常量变量
/// <summary>
/// 我的属性
/// </summary>
public int MyProperty { get; set; }
/// <summary>
/// 我的只读属性
/// </summary>
public string MyReadOnlyProperty { get; internal set; }
/// <summary>
/// 我不能转换的属性
/// </summary>
public Type MyUnconvertibleProperty { get; set; }
/// <summary>
/// 委托回调
/// </summary>
public V8HandlerDelegate CallBack { get; set; }
#endregion 声明常量变量
#region 构造函数
/// <summary>
/// 默认构造函数
/// </summary>
public ExampleBv8Handler()
{
MyProperty = 100;
MyReadOnlyProperty = “flydoos@vip.qq.com”;
MyUnconvertibleProperty = GetType();
}
#endregion 构造函数
#region 事件
/// <summary>
/// 网页脚本与后台程序交互方法
/// 提示一：如果 returnValue = null; 则会导致网页前端出现错误：Cannot read property ’constructor’ of undefined
/// 提示二：还存在其他的可能，导致导致网页前端出现错误：Cannot read property ’constructor’ of undefined
/// </summary>
/// <param name=”name”>名称</param>
/// <param name=”obj”>对象</param>
/// <param name=”arguments”>参数</param>
/// <param name=”returnValue”>返回值</param>
/// <param name=”exception”>返回异常信息</param>
/// <returns></returns>
protected override bool Execute(string name, CefV8Value obj, CefV8Value[] arguments, out CefV8Value returnValue, out string exception)
{
returnValue = CefV8Value.CreateNull();
exception = null;
if (CallBack != null)
{
CallBack(name, obj, arguments, out returnValue, out exception);
}
return true;
}
#endregion 事件
#region 方法
/// <summary>
/// 重复叠加字符串
/// </summary>
/// <param name=”str”>字符串</param>
/// <param name=”n”>次数</param>
/// <returns></returns>
public string Repeat(string str, int n)
{
string result = String.Empty;
for (int i = 0; i < n; i++)
{
result += str;
}
return result;
}
/// <summary>
/// 无返回值
/// </summary>
public void EchoVoid()
{
MessageBox.Show(“BindingTestAv8Handler : EchoVoid()”);
}
/// <summary>
/// 返回逻辑型
/// </summary>
/// <param name=”arg0″>参数</param>
/// <returns></returns>
public Boolean EchoBoolean(Boolean arg0)
{
return arg0;
}
/// <summary>
/// 返回可空逻辑型
/// </summary>
/// <param name=”arg0″>参数</param>
/// <returns></returns>
public Boolean? EchoNullableBoolean(Boolean? arg0)
{
return arg0;
}
/// <summary>
/// 返回 8 位有符号整数
/// </summary>
/// <param name=”arg0″>参数</param>
/// <returns></returns>
public SByte EchoSByte(SByte arg0)
{
return arg0;
}
/// <summary>
/// 返回可空 8 位有符号整数
/// </summary>
/// <param name=”arg0″>参数</param>
/// <returns></returns>
public SByte? EchoNullableSByte(SByte? arg0)
{
return arg0;
}
/// <summary>
/// 返回 16 位有符号整数
/// </summary>
/// <param name=”arg0″>参数</param>
/// <returns></returns>
public Int16 EchoInt16(Int16 arg0)
{
return arg0;
}
/// <summary>
/// 返回可空 16 位有符号整数
/// </summary>
/// <param name=”arg0″>参数</param>
/// <returns></returns>
public Int16? EchoNullableInt16(Int16? arg0)
{
return arg0;
}
/// <summary>
/// 返回 32 位有符号整数
/// </summary>
/// <param name=”arg0″>参数</param>
/// <returns></returns>
public Int32 EchoInt32(Int32 arg0)
{
return arg0;
}
/// <summary>
/// 返回可空 32 位有符号整数
/// </summary>
/// <param name=”arg0″>参数</param>
/// <returns></returns>
public Int32? EchoNullableInt32(Int32? arg0)
{
return arg0;
}
/// <summary>
/// 返回 64 位有符号整数
/// </summary>
/// <param name=”arg0″>参数</param>
/// <returns></returns>
public Int64 EchoInt64(Int64 arg0)
{
return arg0;
}
/// <summary>
/// 返回可空 64 位有符号整数
/// </summary>
/// <param name=”arg0″>参数</param>
/// <returns></returns>
public Int64? EchoNullableInt64(Int64? arg0)
{
return arg0;
}
/// <summary>
/// 返回 8 位无符号整数
/// </summary>
/// <param name=”arg0″>参数</param>
/// <returns></returns>
public Byte EchoByte(Byte arg0)
{
return arg0;
}
/// <summary>
/// 返回可空 8 位无符号整数
/// </summary>
/// <param name=”arg0″>参数</param>
/// <returns></returns>
public Byte? EchoNullableByte(Byte? arg0)
{
return arg0;
}
/// <summary>
/// 返回 16 位无符号整数
/// </summary>
/// <param name=”arg0″>参数</param>
/// <returns></returns>
public UInt16 EchoUInt16(UInt16 arg0)
{
return arg0;
}
/// <summary>
/// 返回可空 16 位无符号整数
/// </summary>
/// <param name=”arg0″>参数</param>
/// <returns></returns>
public UInt16? EchoNullableUInt16(UInt16? arg0)
{
return arg0;
}
/// <summary>
/// 返回 32 位无符号整数
/// </summary>
/// <param name=”arg0″>参数</param>
/// <returns></returns>
public UInt32 EchoUInt32(UInt32 arg0)
{
return arg0;
}
/// <summary>
/// 返回可空 32 位无符号整数
/// </summary>
/// <param name=”arg0″>参数</param>
/// <returns></returns>
public UInt32? EchoNullableUInt32(UInt32? arg0)
{
return arg0;
}
/// <summary>
/// 返回 64 位无符号整数
/// </summary>
/// <param name=”arg0″>参数</param>
/// <returns></returns>
public UInt64 EchoUInt64(UInt64 arg0)
{
return arg0;
}
/// <summary>
/// 返回可空 64 位无符号整数
/// </summary>
/// <param name=”arg0″>参数</param>
/// <returns></returns>
public UInt64? EchoNullableUInt64(UInt64? arg0)
{
return arg0;
}
/// <summary>
/// 返回单精度浮点数
/// </summary>
/// <param name=”arg0″>参数</param>
/// <returns></returns>
public Single EchoSingle(Single arg0)
{
return arg0;
}
/// <summary>
/// 返回可空单精度浮点数
/// </summary>
/// <param name=”arg0″>参数</param>
/// <returns></returns>
public Single? EchoNullableSingle(Single? arg0)
{
return arg0;
}
/// <summary>
/// 返回双精度浮点数
/// </summary>
/// <param name=”arg0″>参数</param>
/// <returns></returns>
public Double EchoDouble(Double arg0)
{
return arg0;
}
/// <summary>
/// 返回可空双精度浮点数
/// </summary>
/// <param name=”arg0″>参数</param>
/// <returns></returns>
public Double? EchoNullableDouble(Double? arg0)
{
return arg0;
}
/// <summary>
/// 返回Unicode字符
/// </summary>
/// <param name=”arg0″>参数</param>
/// <returns></returns>
public Char EchoChar(Char arg0)
{
return arg0;
}
/// <summary>
/// 返回可空Unicode字符
/// </summary>
/// <param name=”arg0″>参数</param>
/// <returns></returns>
public Char? EchoNullableChar(Char? arg0)
{
return arg0;
}
/// <summary>
/// 返回时间类型
/// </summary>
/// <param name=”arg0″>参数</param>
/// <returns></returns>
public DateTime EchoDateTime(DateTime arg0)
{
return arg0;
}
/// <summary>
/// 返回可空时间类型
/// </summary>
/// <param name=”arg0″>参数</param>
/// <returns></returns>
public DateTime? EchoNullableDateTime(DateTime? arg0)
{
return arg0;
}
/// <summary>
/// 返回十进制数
/// </summary>
/// <param name=”arg0″>参数</param>
/// <returns></returns>
public Decimal EchoDecimal(Decimal arg0)
{
return arg0;
}
/// <summary>
/// 返回可空十进制数
/// </summary>
/// <param name=”arg0″>参数</param>
/// <returns></returns>
public Decimal? EchoNullableDecimal(Decimal? arg0)
{
return arg0;
}
/// <summary>
/// 返回字符串
/// </summary>
/// <param name=”arg0″>参数</param>
/// <returns></returns>
public String EchoString(String arg0)
{
return arg0;
}
/// <summary>
/// 转为小写
/// </summary>
/// <param name=”arg0″>参数</param>
/// <returns></returns>
public String LowercaseMethod(String arg0)
{
String result = String.Empty;
if (arg0 != null)
{
result = arg0.ToLower();
}
MessageBox.Show(“BindingTestAv8Handler : ” + result);
return result;
}
#endregion 方法
}
2.3 评价总结：
优势：
(1)、与方法一相比，这个的优势在于不需要在类内部（ExampleBv8Handler），写操作代码。因为有些操作必须在外面编写的，通过回调可以解决这个问题。
弊端：
(1)、弊端与方法一类似，很不灵活；
form：http://www.wuleba.com/23620.html