为什么self.isdisabled=true;不能立即把按钮状态改为禁用！？如何立即生效，防止重复提交

 
 <van-button round block type="info" native-type="submit" style="margin-top: 5px;" :disabled="isdisabled" >
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            </van-button>
 

 onSubmit_wenku(values) {
                var self=this;
                self.isdisabled=true;
 
                //优化校验逻辑
                ajaxPostNoAsyncJson("/Wenku", values, function (datastr) {
                    self.SmsCount = datastr.SmsCount
                    if (datastr.state == true) {
 
                        vant.Dialog.alert({
                            message: datastr.msg,
                        }).then(() => {
                            
                            self.onLoadMydown();
                        });
                        self.wenku_url = ""
                    } else {
                        
                        vant.Dialog.alert({
                            message: datastr.msg,
                        }).then(() => {
                            self.$refs.wenku_url_html.focus();
                        });

                    }
                    self.isdisabled=false;
                })


            },