diff --git a/changelog.md b/changelog.md
index 3c1fc91be..78c07f643 100644
--- a/changelog.md
+++ b/changelog.md
@@ -1,5 +1,6 @@
 # 更新日志
 2.0(2021-12)
+- childContext废弃，替换成provide
 - 支持BI.useContext获取上下文环境
 - BI.Msg.alert支持message传json格式
 - 支持BI.config(function(){})进行系统配置
diff --git a/dist/fix/fix.js b/dist/fix/fix.js
index 3e93f1601..54ae610ef 100644
--- a/dist/fix/fix.js
+++ b/dist/fix/fix.js
@@ -134,8 +134,8 @@ function _classCallCheck(instance, Constructor) { if (!(instance instanceof Cons
                 setImmediate(nextTickHandler);
             };
         } else if (typeof MessageChannel !== 'undefined' && (isNative(MessageChannel) ||
-            // PhantomJS
-            MessageChannel.toString() === '[object MessageChannelConstructor]')) {
+        // PhantomJS
+        MessageChannel.toString() === '[object MessageChannelConstructor]')) {
             var channel = new MessageChannel();
             var port = channel.port2;
             channel.port1.onmessage = nextTickHandler;
@@ -144,18 +144,18 @@ function _classCallCheck(instance, Constructor) { if (!(instance instanceof Cons
             };
         } else
             /* istanbul ignore next */
-        if (typeof Promise !== 'undefined' && isNative(Promise)) {
-            // use microtask in non-DOM environments, e.g. Weex
-            var p = Promise.resolve();
-            timerFunc = function timerFunc() {
-                p.then(nextTickHandler);
-            };
-        } else {
-            // fallback to setTimeout
-            timerFunc = function timerFunc() {
-                setTimeout(nextTickHandler, 0);
-            };
-        }
+            if (typeof Promise !== 'undefined' && isNative(Promise)) {
+                // use microtask in non-DOM environments, e.g. Weex
+                var p = Promise.resolve();
+                timerFunc = function timerFunc() {
+                    p.then(nextTickHandler);
+                };
+            } else {
+                // fallback to setTimeout
+                timerFunc = function timerFunc() {
+                    setTimeout(nextTickHandler, 0);
+                };
+            }
 
         return function queueNextTick(cb, ctx) {
             var _resolve = void 0;
@@ -294,7 +294,7 @@ function _classCallCheck(instance, Constructor) { if (!(instance instanceof Cons
         if (isIE9Below) {
             var VBClassPool = {};
             window.execScript([// jshint ignore:line
-                'Function parseVB(code)', '\tExecuteGlobal(code)', 'End Function' //转换一段文本为VB代码
+            'Function parseVB(code)', '\tExecuteGlobal(code)', 'End Function' //转换一段文本为VB代码
             ].join('\n'), 'VBScript');
 
             var VBMediator = function VBMediator(instance, accessors, name, value) {
@@ -310,7 +310,7 @@ function _classCallCheck(instance, Constructor) { if (!(instance instanceof Cons
                 // jshint ignore:line
                 var buffer = [];
                 buffer.push('\tPrivate [$vbsetter]', '\tPublic  [$accessors]', '\tPublic Default Function [$vbthis](ac' + timeBucket + ', s' + timeBucket + ')', '\t\tSet  [$accessors] = ac' + timeBucket + ': set [$vbsetter] = s' + timeBucket, '\t\tSet  [$vbthis]    = Me', //链式调用
-                    '\tEnd Function');
+                '\tEnd Function');
                 //添加普通属性,因为VBScript对象不能像JS那样随意增删属性，必须在这里预先定义好
                 var uniq = {
                     $vbthis: true,
@@ -323,19 +323,19 @@ function _classCallCheck(instance, Constructor) { if (!(instance instanceof Cons
                         uniq[name] = true;
                     }
                 }
-                //添加访问器属性
+                //添加访问器属性 
                 for (name in accessors) {
                     if (uniq[name]) {
                         continue;
                     }
                     uniq[name] = true;
                     buffer.push(
-                        //由于不知对方会传入什么,因此set, let都用上
-                        '\tPublic Property Let [' + name + '](val' + timeBucket + ')', //setter
-                        '\t\tCall [$vbsetter](Me, [$accessors], "' + name + '", val' + timeBucket + ')', '\tEnd Property', '\tPublic Property Set [' + name + '](val' + timeBucket + ')', //setter
-                        '\t\tCall [$vbsetter](Me, [$accessors], "' + name + '", val' + timeBucket + ')', '\tEnd Property', '\tPublic Property Get [' + name + ']', //getter
-                        '\tOn Error Resume Next', //必须优先使用set语句,否则它会误将数组当字符串返回
-                        '\t\tSet[' + name + '] = [$vbsetter](Me, [$accessors],"' + name + '")', '\tIf Err.Number <> 0 Then', '\t\t[' + name + '] = [$vbsetter](Me, [$accessors],"' + name + '")', '\tEnd If', '\tOn Error Goto 0', '\tEnd Property');
+                    //由于不知对方会传入什么,因此set, let都用上
+                    '\tPublic Property Let [' + name + '](val' + timeBucket + ')', //setter
+                    '\t\tCall [$vbsetter](Me, [$accessors], "' + name + '", val' + timeBucket + ')', '\tEnd Property', '\tPublic Property Set [' + name + '](val' + timeBucket + ')', //setter
+                    '\t\tCall [$vbsetter](Me, [$accessors], "' + name + '", val' + timeBucket + ')', '\tEnd Property', '\tPublic Property Get [' + name + ']', //getter
+                    '\tOn Error Resume Next', //必须优先使用set语句,否则它会误将数组当字符串返回
+                    '\t\tSet[' + name + '] = [$vbsetter](Me, [$accessors],"' + name + '")', '\tIf Err.Number <> 0 Then', '\t\t[' + name + '] = [$vbsetter](Me, [$accessors],"' + name + '")', '\tEnd If', '\tOn Error Goto 0', '\tEnd Property');
                 }
 
                 for (name in properties) {
@@ -353,7 +353,7 @@ function _classCallCheck(instance, Constructor) { if (!(instance instanceof Cons
                     className = makeHashCode('VBClass');
                     window.parseVB('Class ' + className + body);
                     window.parseVB(['Function ' + className + 'Factory(acc, vbm)', //创建实例并传入两个关键的参数
-                        '\tDim o', '\tSet o = (New ' + className + ')(acc, vbm)', '\tSet ' + className + 'Factory = o', 'End Function'].join('\r\n'));
+                    '\tDim o', '\tSet o = (New ' + className + ')(acc, vbm)', '\tSet ' + className + 'Factory = o', 'End Function'].join('\r\n'));
                     VBClassPool[body] = className;
                 }
                 var ret = window[className + 'Factory'](accessors, VBMediator); //得到其产品
@@ -537,10 +537,10 @@ function _classCallCheck(instance, Constructor) { if (!(instance instanceof Cons
             if (this.active) {
                 var value = this.get();
                 if (value !== this.value ||
-                    // Deep watchers and watchers on Object/Arrays should fire even
-                    // when the value is the same, because the value may
-                    // have mutated.
-                    _.isObject(value) && options && options.refresh || this.deep) {
+                // Deep watchers and watchers on Object/Arrays should fire even
+                // when the value is the same, because the value may
+                // have mutated.
+                _.isObject(value) && options && options.refresh || this.deep) {
                     // set new value
                     var oldValue = this.value;
                     this.value = value;
@@ -1420,12 +1420,15 @@ function _classCallCheck(instance, Constructor) { if (!(instance instanceof Cons
             var context = this.context;
             var inject = this.inject;
             var childContext = this.childContext;
+            var provide = this.provide;
             var watch$$1 = this.watch;
             var actions = this.actions;
             var keys = _.keys(this.$$model).concat(_.keys(state)).concat(_.keys(computed)).concat(inject || []).concat(context || []);
             var mixins = this.mixins;
             defineProps(this, keys);
+            // deprecated
             childContext && defineContext(this, childContext);
+            provide && defineContext(this, provide);
             this.$$model && (this.model.__ob__ = this.$$model.__ob__);
             initMixins(this, mixins);
             this.init();
@@ -1523,4 +1526,4 @@ function _classCallCheck(instance, Constructor) { if (!(instance instanceof Cons
     exports.toJSON = toJSON;
 
     exports.__esModule = true;
-});
+});
\ No newline at end of file
diff --git a/src/core/4.widget.js b/src/core/4.widget.js
index f8fe45929..5de5d7c85 100644
--- a/src/core/4.widget.js
+++ b/src/core/4.widget.js
@@ -768,38 +768,50 @@
         }
     };
 
-    BI.useContext = function () {
+    BI.useContext = function (inject) {
+        if (BI.Model.target) {
+            var p = BI.Model.target;
+            if (inject) {
+                while (p) {
+                    if (p.$$context && inject in p.$$context) {
+                        return p;
+                    }
+                    p = p._parent;
+                }
+            }
+        }
         return BI.Model.target;
     };
 
     BI.watch = function (vm, watch, handler) {
-        if (vm instanceof BI.Model) {
-            var watchers = [];
-            if (BI.isKey(watch)) {
-                var k = watch;
-                watch = {};
-                watch[k] = handler;
-            }
-            for (var key in watch) {
-                var innerHandler = watch[key];
-                if (BI.isArray(handler)) {
-                    for (var i = 0; i < handler.length; i++) {
+        // 必须要保证组件当前环境存在
+        if (BI.Widget.current) {
+            if (vm instanceof BI.Model) {
+                var watchers = [];
+                if (BI.isKey(watch)) {
+                    var k = watch;
+                    watch = {};
+                    watch[k] = handler;
+                }
+                for (var key in watch) {
+                    var innerHandler = watch[key];
+                    if (BI.isArray(handler)) {
+                        for (var i = 0; i < handler.length; i++) {
+                            watchers.push(Fix.watch(vm.model, key, innerHandler, {
+                                store: vm
+                            }));
+                        }
+                    } else {
                         watchers.push(Fix.watch(vm.model, key, innerHandler, {
                             store: vm
                         }));
                     }
-                } else {
-                    watchers.push(Fix.watch(vm.model, key, innerHandler, {
-                        store: vm
-                    }));
                 }
+                // vm中一定有_widget
+                BI.Widget.current._watchers || (BI.Widget.current._watchers = []);
+                BI.Widget.current._watchers = BI.Widget.current._watchers.concat(watchers);
+                return;
             }
-            // vm中一定有_widget
-            vm._widget._watchers || (vm._widget._watchers = []);
-            vm._widget._watchers = vm._widget._watchers.concat(watchers);
-            return;
-        }
-        if (BI.Widget.current) {
             handler = watch;
             watch = vm;
             BI.Widget.current.$watchDelayCallbacks || (BI.Widget.current.$watchDelayCallbacks = []);