我有两个现有的表(TableA和TableB),我需要向TableA添加一个新列,该列具有TableB的外键并且具有非null的默认值...并且这两个约束都需要命名.我怎样才能做到这一点?
与C++不同,在C#中,您不能重载赋值运算符.
我正在为具有非常大数字的算术运算做一个自定义Number类,我希望它具有内置数值类型的外观,如int,decimal等.我已经重载了算术运算符,但是任务仍然是......
这是一个例子:
Number a = new Number(55);
Number b = a; //I want to copy the value, not the reference
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该问题是否有解决方法?
为什么新Code Lens
选项在Visual Studio 2013 Professional中不可用?如何将其添加(返回?)到VS2013中?
它应该如何显示的示例:
有关我的选项如何显示的示例:
按照Xamarin站点上的步骤绑定Java库以创建ArcGIS for Android 10.2.2的绑定项目时,我可以编译项目.但是,当我尝试部署并运行项目时,我收到以下错误:
COMPILETODALVIK : UNEXPECTED TOP-LEVEL error :
java.lang.OutOfMemoryError: Java heap space
at java.util.Arrays.copyOf(Arrays.java:2760)
at java.util.Arrays.copyOf(Arrays.java:2734)
at java.util.ArrayList.ensureCapacity(ArrayList.java:167)
at java.util.ArrayList.add(ArrayList.java:351)
at com.android.dx.ssa.SsaMethod$2.addToUses(SsaMethod.java:474)
at com.android.dx.ssa.SsaMethod$2.visitPhiInsn(SsaMethod.java:459)
at com.android.dx.ssa.PhiInsn.accept(PhiInsn.java:323)
at com.android.dx.ssa.SsaBasicBlock.forEachInsn(SsaBasicBlock.java:990)
at com.android.dx.ssa.SsaMethod.forEachInsn(SsaMethod.java:729)
at com.android.dx.ssa.SsaMethod.buildUseList(SsaMethod.java:452)
at com.android.dx.ssa.SsaMethod.getUseListForRegister(SsaMethod.java:641)
at com.android.dx.ssa.SCCP.addUsersToWorklist(SCCP.java:116)
at com.android.dx.ssa.SCCP.simulateStmt(SCCP.java:538)
at com.android.dx.ssa.SCCP.simulateBlock(SCCP.java:208)
at com.android.dx.ssa.SCCP.run(SCCP.java:554)
at com.android.dx.ssa.SCCP.process(SCCP.java:92)
at com.android.dx.ssa.Optimizer.runSsaFormSteps(Optimizer.java:160)
at com.android.dx.ssa.Optimizer.optimize(Optimizer.java:100)
at com.android.dx.ssa.Optimizer.optimize(Optimizer.java:73)
at com.android.dx.dex.cf.CfTranslator.processMethods(CfTranslator.java:273)
at com.android.dx.dex.cf.CfTranslator.translate0(CfTranslator.java:134)
at com.android.dx.dex.cf.CfTranslator.translate(CfTranslator.java:87)
at com.android.dx.command.dexer.Main.processClass(Main.java:487)
at com.android.dx.command.dexer.Main.processFileBytes(Main.java:459)
at com.android.dx.command.dexer.Main.access$400(Main.java:67)
at com.android.dx.command.dexer.Main$1.processFileBytes(Main.java:398)
at com.android.dx.cf.direct.ClassPathOpener.processArchive(ClassPathOpener.java:245)
at com.android.dx.cf.direct.ClassPathOpener.processOne(ClassPathOpener.java:131)
at com.android.dx.cf.direct.ClassPathOpener.process(ClassPathOpener.java:109)
at com.android.dx.command.dexer.Main.processOne(Main.java:422)
at com.android.dx.command.dexer.Main.processAllFiles(Main.java:333)
at com.android.dx.command.dexer.Main.run(Main.java:209)
Run Code Online (Sandbox Code Playgroud) 我有一个网页,用户可以通过ASP.NET Web处理程序(.ashx
)下载PDF文件.它的实现就像这个问题的答案一样.我遇到的问题是当我window.top.location.href = url;
在我的JavaScript中执行此操作时,如果处理程序中抛出异常,我无法真正控制会发生什么.当一切正常时,用户体验是他们基本上停留在他们所在的页面上,并且浏览器告诉他们他们可以下载PDF文件.但是,当处理程序中抛出异常时,它们会被重定向到处理程序的URL并显示一个空白页面.
以下是一些示例代码,使其更加清晰:
JavaScript的:
function openPDF() {
var url = GeneratePDFUrl();
window.top.location.href = url;
}
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处理器:
public override void Process(HttpContext context)
{
byte[] pdfdata = GetPDFData();
context.Response.ContentType = "application/pdf";
context.Response.AddHeader("content-disposition", "attachment; filename=\"" + GetPDFFileName() + "\"");
context.Response.AddHeader("content-length", pdfdata.Length.ToString());
context.Response.BinaryWrite(pdfdata);
}
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GetPDFData()抛出异常时会发生此问题.我们正在尽我们所能阻止GetPDFData()抛出异常,但它是从用户输入生成的,所以我们也在这里处理它,以防有时我们不能/无法预测哪些会产生错误.
这是我提出的一个解决方案,但它显示了用户错误文本(而不是空白页)
public override void Process(HttpContext context)
{
try
{
byte[] pdfdata = GetPDFData();
WritePDF(pdfdata, GetPDFFileName()); // Executes code in example above
}
catch (Exception e)
{
context.Response.Clear();
context.Response.Write(GetErrorMessage(e));
}
}
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理想情况下,我想向用户显示一个弹出窗口,以便他们留在他们所在的页面上.
更新:我已经能够将我的应用程序部署到Android API级别10,15,17,18.所以这似乎是API 19的一个问题.
当我尝试调试我的应用程序(MvvmCross
"Hello World"应用程序)时,它不会在Intel Atom(x86)模拟器中启动,但是应用程序确实启动到ARM(armeabi-v7a)模拟器中.当尝试在Intel Atom(x86)模拟器中启动时,Visual Studio 2013成功启动模拟器,执行构建应用程序,然后在构建后挂起并说Waiting for device...
,但模拟器已启动并运行,响应并出现工作正常.一旦我关闭模拟器,Visual Studio 2013/Xamarin就会弹出这个错误:
细节只是说没有找到模拟器 - 所以环境知道模拟器以及它何时运行以及何时不运行.
Visual Studio 2013的输出 - 构建窗口
2>Build succeeded.
2> 0 Warning(s)
2> 0 Error(s)
2>
2>Time Elapsed 00:00:13.60
2>
2>
2>
2>Waiting for device..
环境:
尽职调查:
在命令行运行时,adb devices
它显示模拟器已启动并正在运行.
我关闭并重新启动Visual Studio 2013和模拟器.
我尝试首先加载模拟器,然后调试,但仍然有同样的问题.
之前,我能走到今天,我有问题与HAXM未安装,但这个不是我有问题.
我查看了Xamarin设置说明,并验证了x86 …
Recyclerview升级到v23.4.0然后发现此崩溃:
java.lang.IllegalArgumentException: view is not a child, cannot hide com.xxx.ViewGroupGridView{32112cd4 V.E..... .......D 0,1443-1080,2277 #7f0b161c app:id/gv_menu_list}
android.support.v7.widget.ChildHelper.unhide(ChildHelper.java:352)
android.support.v7.widget.RecyclerView$Recycler.getScrapViewForPosition(RecyclerView.java:5080)
android.support.v7.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:4634)
android.support.v7.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:4617)
android.support.v7.widget.LinearLayoutManager$LayoutState.next(LinearLayoutManager.java:1994)
android.support.v7.widget.LinearLayoutManager.layoutChunk(LinearLayoutManager.java:1390)
android.support.v7.widget.LinearLayoutManager.fill(LinearLayoutManager.java:1353)
android.support.v7.widget.LinearLayoutManager.onLayoutChildren(LinearLayoutManager.java:584)
android.support.v7.widget.RecyclerView.dispatchLayoutStep2(RecyclerView.java:3028)
android.support.v7.widget.RecyclerView.onMeasure(RecyclerView.java:2625)
android.view.View.measure(View.java:17788)
android.widget.RelativeLayout.measureChild(RelativeLayout.java:816)
android.widget.RelativeLayout.onMeasure(RelativeLayout.java:561)
android.view.View.measure(View.java:17788)
android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5636)
android.widget.FrameLayout.onMeasure(FrameLayout.java:459)
android.view.View.measure(View.java:17788)
android.widget.RelativeLayout.measureChildHorizontal(RelativeLayout.java:846)
android.widget.RelativeLayout.onMeasure(RelativeLayout.java:512)
android.view.View.measure(View.java:17788)
android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5636)
android.widget.FrameLayout.onMeasure(FrameLayout.java:459)
android.view.View.measure(View.java:17788)
android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5636)
android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1692)
android.widget.LinearLayout.measureVertical(LinearLayout.java:760)
android.widget.LinearLayout.onMeasure(LinearLayout.java:629)
android.view.View.measure(View.java:17788)
android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5636)
android.widget.FrameLayout.onMeasure(FrameLayout.java:459)
com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2712)
android.view.View.measure(View.java:17788)
android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:2482)
android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1436)
android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1704)
android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1314)
android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:6715)
android.view.Choreographer$CallbackRecord.run(Choreographer.java:800)
android.view.Choreographer.doCallbacks(Choreographer.java:603)
android.view.Choreographer.doFrame(Choreographer.java:572)
android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:786)
android.os.Handler.handleCallback(Handler.java:815)
android.os.Handler.dispatchMessage(Handler.java:104)
android.os.Looper.loop(Looper.java:213)
android.app.ActivityThread.main(ActivityThread.java:5819)
java.lang.reflect.Method.invoke(Native Method)
java.lang.reflect.Method.invoke(Method.java:372)
com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:998)
com.android.internal.os.ZygoteInit.main(ZygoteInit.java:793)
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这是布局文件. ViewGroupGridView是一个扩展linearLayout的常见视图,我只是在RecyclerView中使用这个绑定数据.
我一直致力于SSRS与我们的Web应用程序的SSO集成,但我无法让它工作.我已经按照MSFT的Clife Green的例子进行了操作,仍然无法使其工作:
Reporting Services单点登录(SSO)身份验证 - 第1部分
Reporting Services单点登录(SSO)身份验证 - 第2部分
我已经浏览了互联网并搜索了MSDN文档但仍无法使其工作.我不断得到的错误是从示例代码中抛出GetWebResponse是这样的:
Authorization ticket not received by LogonUser
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我能够通过来回传递自己的cookie来检查它,同时忽略SSRS管理的cookie,但是我所做的所有调用都返回为Unauthenticated,因为我没有使用在SSRS中返回的SSRS会话令牌. LogonUser可以在响应中找到:
response.Headers["RSAuthenticationHeader"]
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但是,即使我的Web服务调用继续工作,报表管理器也无法正常工作并返回此错误:
StringStartsWith can't accept null parameters
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