我有一个服务来上传许多大块文件
export default Ember.Service.extend({
run(files, callbacks) {
// ugly async FileReader and ajax
// calling callbacks during the process
}
})
我需要一堆回调来显示进度，但问题是this在这些回调中未定义
export default Ember.Component.extend({
upload: Ember.inject.service(),
didInsertElement() {
// bind fileinput change event to set up pending files
},
ondonesingle(self, file, uuid) {
// this is undefined
// self is real this
},
actions: {
submit() {
let callbacks = {
ondoneall: this.ondoneall,
ondonesingle: this.ondonesingle,
onprogressall: this.onprogressall,
onprogresssingle: this.onprogresssingle,
onerror: this.onerror,
object: this // will be passed as first argument to each callback
};
this.get('upload').run(this.get('pending_files'), callbacks);
},
}
})
要解决这个问题，我必须随处参考。
它有效，但感觉非常错误。在恩伯最好的做法是什么？可观察的属性也感觉不对，我如何观察2000个文件的进度？将所有内容放在一个大对象中并在整个应用程序中共享它？
答案 0 :(得分：2)
Shader "Custom/Blur" {
Properties {
_Color ("Main Color", Color) = (1,1,1,1)
_BumpAmt ("Distortion", Range (0,128)) = 10
_MainTex ("Tint Color (RGB)", 2D) = "white" {}
_BumpMap ("Normalmap", 2D) = "bump" {}
_HorizontalDistort ("Horizontal Distortion", Float) = 1.0
_VerticalDistort ("Vertical Distortion", Float) = 1.0
}
Category {
// We must be transparent, so other objects are drawn before this one.
Tags { "Queue"="Transparent" "IgnoreProjector"="True" "RenderType"="Opaque" }
SubShader {
// Horizontal blur
GrabPass {
Tags { "LightMode" = "Always" }
}
Pass {
Tags { "LightMode" = "Always" }
CGPROGRAM
#pragma vertex vert
#pragma fragment frag
#pragma fragmentoption ARB_precision_hint_fastest
#include "UnityCG.cginc"
struct v2f {
float4 vertex : POSITION;
float4 uvgrab : TEXCOORD0;
};
v2f vert (v2f v) {
v2f o;
o.vertex = mul(UNITY_MATRIX_MVP, v.vertex);
#if UNITY_UV_STARTS_AT_TOP // Only true in directX platforms
float scale = -1.0;
#else
float scale = 1.0;
#endif
o.uvgrab.xy = (float2(o.vertex.x, o.vertex.y*scale) + o.vertex.w) * 0.5;
o.uvgrab.zw = o.vertex.zw;
return o;
}
sampler2D _GrabTexture;
float4 _GrabTexture_TexelSize;
float _HorizontalDistort;
half4 frag( v2f i ) : COLOR {
half4 sum = half4(0,0,0,0);
#define GRABPIXEL(kernelx) tex2Dproj( _GrabTexture, UNITY_PROJ_COORD(float4(i.uvgrab.x + _GrabTexture_TexelSize.x * kernelx*_HorizontalDistort, i.uvgrab.y, i.uvgrab.z, i.uvgrab.w)))
sum += GRABPIXEL(-4.0) * 0.05;
sum += GRABPIXEL(-3.0) * 0.09;
sum += GRABPIXEL(-2.0) * 0.12;
sum += GRABPIXEL(-1.0) * 0.15;
sum += GRABPIXEL(0.0) * 0.18;
sum += GRABPIXEL(+1.0) * 0.15;
sum += GRABPIXEL(+2.0) * 0.12;
sum += GRABPIXEL(+3.0) * 0.09;
sum += GRABPIXEL(+4.0) * 0.05;
return sum;
}
ENDCG
}
// Vertical blur
GrabPass {
Tags { "LightMode" = "Always" }
}
Pass {
Tags { "LightMode" = "Always" }
CGPROGRAM
#pragma vertex vert
#pragma fragment frag
#pragma fragmentoption ARB_precision_hint_fastest
#include "UnityCG.cginc"
struct v2f {
float4 vertex : POSITION;
float4 uvgrab : TEXCOORD0;
};
v2f vert (v2f v) {
v2f o;
o.vertex = mul(UNITY_MATRIX_MVP, v.vertex);
#if UNITY_UV_STARTS_AT_TOP
float scale = -1.0;
#else
float scale = 1.0;
#endif
o.uvgrab.xy = (float2(o.vertex.x, o.vertex.y*scale) + o.vertex.w) * 0.5;
o.uvgrab.zw = o.vertex.zw;
return o;
}
sampler2D _GrabTexture;
float4 _GrabTexture_TexelSize;
float _VerticalDistort;
half4 frag( v2f i ) : COLOR {
half4 sum = half4(0,0,0,0);
#define GRABPIXEL(kernely) tex2Dproj(_GrabTexture, UNITY_PROJ_COORD(float4(i.uvgrab.x, i.uvgrab.y + _GrabTexture_TexelSize.y * kernely*_VerticalDistort, i.uvgrab.z, i.uvgrab.w)))
sum += GRABPIXEL(-4.0) * 0.05;
sum += GRABPIXEL(-3.0) * 0.09;
sum += GRABPIXEL(-2.0) * 0.12;
sum += GRABPIXEL(-1.0) * 0.15;
sum += GRABPIXEL(0.0) * 0.18;
sum += GRABPIXEL(+1.0) * 0.15;
sum += GRABPIXEL(+2.0) * 0.12;
sum += GRABPIXEL(+3.0) * 0.09;
sum += GRABPIXEL(+4.0) * 0.05;
return sum;
}
ENDCG
}
}
}
}
回来this的原因是当函数传递时它的上下文（undefined）发生了变化。您可以创建一个新函数，使用this显式设置其上下文。使用function.bind时，无论您在何处调用新函数或将其赋值给的值/属性，它的上下文都将保持不变。
see MDN for Function.prototype.bind
function.bind