小编TTG*_*oup的帖子

我在Win32控制台应用程序中有2个文件,A.cpp和B.cpp.

这2个文件只包含以下2行代码:

#include "stdafx.h"
int k;

编译时会产生错误

Error   1   error LNK2005: "int k" (?a@@3HA) already defined in A.obj

我不明白发生了什么.

有人可以向我解释一下吗？

我在C#上使用WPF代码如下

<Window       
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" mc:Ignorable="d"
    xmlns:utility="clr-namespace:DVRClientInterface.Utility"
    xmlns:toolkit="http://schemas.xceed.com/wpf/xaml/toolkit"     
    xmlns:wpftoolkit="clr-namespace:Microsoft.Windows.Controls;assembly=WPFToolkit"   
    xmlns:customControl="clr-namespace:DVRClientInterface.CustomControls"    
    x:Class="DVRClientInterface.MainWindow"
    WindowStyle="None" ResizeMode="CanMinimize"
    AllowsTransparency="True"
    WindowState = "Maximized"
    WindowStartupLocation="CenterScreen"    
    StateChanged="Window_StateChanged" 
    KeyUp="Window_KeyUp" 
    KeyDown="Window_KeyDown"    
    Closing="Window_Closing" Loaded="Window_Loaded"
     >
    <!-- WindowState = "Maximized" -->
    <Window.Background>
        <ImageBrush ImageSource="Resources\main_background.png"/>
    </Window.Background>

    <Grid x:Name="MainWindowGrid">
     //My GUI Code here

    </Grid>
</Window>

当我运行应用程序时,它将抛出以下异常

An unhandled exception of type 'System.Windows.Markup.XamlParseException' occurred in PresentationFramework.dll

Additional information: 'The invocation of the constructor on type 'DVRClientInterface.MainWindow' that matches the specified binding constraints threw an exception.' Line number '9' and line position '5'.

If there …

我想从IntPtr指针获取数据到字节数组.我可以使用以下代码来执行此操作:

IntPtr intPtr = GetBuff();
byte[] b = new byte[length];
Marshal.Copy(intPtr, b, 0, length);

但是上面的代码强制从IntPtr到字节数组的复制操作.当有问题的数据很大时,这不是一个好的解决方案.

有没有办法将IntPtr转换为字节数组？例如,以下工作:

byte[] b = (byte[])intPtr

这将消除复制操作的需要.

另外:我们如何确定IntPtr指向的数据长度？

我正在使用WPF(C#)的进度条来描述进程的进度.

我的算法如下:

DoSomethingCode1();
ProgressBar.SetPercent(10); // 10%
DoSomethingCode2();
ProgressBar.SetPercent(20); // 20%

...

DoSomethingCode10();
ProgressBar.SetPercent(100); // 100%

没关系,但它会使进度条不连续.

有人可以告诉我一些让进度条轻柔更新的建议吗？

我想使用c ++代码从位图图像制作.avi视频文件.我写了以下代码:

//Get RGB array data from bmp file
uint8_t* rgb24Data = new uint8_t[3*imgWidth*imgHeight];
hBitmap = (HBITMAP) LoadImage( NULL, _T("myfile.bmp"), IMAGE_BITMAP, 0, 0, LR_LOADFROMFILE);
GetDIBits(hdc, hBitmap, 0, imgHeight, rgb24Data , (BITMAPINFO*)&bmi, DIB_RGB_COLORS);

/* Allocate the encoded raw picture. */
AVPicture dst_picture;
avpicture_alloc(&dst_picture, AV_PIX_FMT_YUV420P, imgWidth, imgHeight);

/* Convert rgb24Data to YUV420p and stored into array dst_picture.data */
RGB24toYUV420P(imgWidth, imgHeight, rgb24Data, dst_picture.data); //How to implement this function?

//code for encode frame dst_picture here

我的问题是如何实现RGB24toYUV420P()函数,这个函数会将RGB24数据从数组rgb24Data 转换为YUV420p存储到dst_picture.data …

我正在使用VisualTreeHelper.GetChildrenCount()查找子控件,但它总是返回0.

这是我的代码

<ScrollViewer x:Name="scrollViewerChannelsRecordTimeData">
    <StackPanel x:Name="channelsRecordTimeData">
        <ItemsControl x:Name="channelRecordTimeItems" ItemsSource="{Binding}">
            <ItemsControl.ItemTemplate>
                <DataTemplate>
                    <Grid x:Name="hoursLines">
                        //Some Controls here                            
                    </Grid>
                </DataTemplate>
            </ItemsControl.ItemTemplate>
        </ItemsControl>
    </StackPanel>
</ScrollViewer>   

C#代码:

channelRecordTimeItems.ItemContainerGenerator.StatusChanged += ChannelRecordTimeItemsStatusChangedEventHandler;
private void ChannelRecordTimeItemsStatusChangedEventHandler(Object sender, EventArgs e)
{
    if (channelRecordTimeItems.ItemContainerGenerator.Status == GeneratorStatus.ContainersGenerated)
    {
        if (channelRecordTimeItems.HasItems)
        {
            DependencyObject dependencyObject = null;
            Grid gridHighlightRecordData = null;
            for (int i = 0; i < channelRecordTimeItems.Items.Count; i++)
            {
                dependencyObject = channelRecordTimeItems.ItemContainerGenerator.ContainerFromIndex(i); //dependencyObject != null
                 if (dependencyObject != null)
                 {
                    Grid hoursLines = FindElement.FindChild<Grid>(dependencyObject, "hoursLines"); //hoursLines = null …

我在C#上使用wpf来设计GUI,我想从xaml代码中获取屏幕大小(宽度和高度的值).

我知道如何从C#代码中获取它们

   Width = System.Windows.Forms.Screen.PrimaryScreen.Bounds.Width;
   Height = System.Windows.Forms.Screen.PrimaryScreen.Bounds.Height;

但我不知道如何从XAML代码中获取它们.

我使用WPF,我感到困惑的执行顺序Control.Dispatcher.BeginInvoke()和Control.Dispatcher.Invoke().

我将在下面展示一个代码示例

backgroundThread = new Thread(BackgroundThread);
backgroundThread.Start();
public void BackgroundThread()
{
    this.Dispatcher.BeginInvoke(new Action(delegate()
    {
      WriteLog("Run command 1");
    }));

    this.Dispatcher.Invoke(new Action(delegate()
    {
      WriteLog("Run command 2");
    }));
}

我希望"命令1"将在"命令2"之前运行并完成,但有时似乎"命令2"在"命令1"之前运行.我对互联网和MSDN文档进行了很多研究,但我不明白为什么会这样.

有人请告诉我这些功能的规则究竟是什么？

非常感谢!

T&T

我正在使用 DirectX 来绘制视频。通过Intel Media SDK解码后。然后我通过以下英特尔代码绘制它：

mfxStatus CD3D11Device::RenderFrame(mfxFrameSurface1 * pSrf, mfxFrameAllocator * pAlloc)
{
    HRESULT hres = S_OK;
    mfxStatus sts;

    sts = CreateVideoProcessor(pSrf);
    MSDK_CHECK_STATUS(sts, "CreateVideoProcessor failed");

    hres = m_pSwapChain->GetBuffer(0, __uuidof( ID3D11Texture2D ), (void**)&m_pDXGIBackBuffer.p);
    if (FAILED(hres))
        return MFX_ERR_DEVICE_FAILED;

    D3D11_VIDEO_PROCESSOR_OUTPUT_VIEW_DESC OutputViewDesc;
    if (2 == m_nViews)
    {
        m_pVideoContext->VideoProcessorSetStreamStereoFormat(m_pVideoProcessor, 0, TRUE,D3D11_VIDEO_PROCESSOR_STEREO_FORMAT_SEPARATE,
            TRUE, TRUE, D3D11_VIDEO_PROCESSOR_STEREO_FLIP_NONE, NULL);
        m_pVideoContext->VideoProcessorSetOutputStereoMode(m_pVideoProcessor,TRUE);

        OutputViewDesc.ViewDimension = D3D11_VPOV_DIMENSION_TEXTURE2DARRAY;
        OutputViewDesc.Texture2DArray.ArraySize = 2;
        OutputViewDesc.Texture2DArray.MipSlice = 0;
        OutputViewDesc.Texture2DArray.FirstArraySlice = 0;
    }
    else
    {
        OutputViewDesc.ViewDimension = D3D11_VPOV_DIMENSION_TEXTURE2D;
        OutputViewDesc.Texture2D.MipSlice = 0;
    }

    if (1 == m_nViews || 0 == …

我想使用 dllexport 导出函数。但是我在编译器“错误 C4439：'WrappedC'：签名中具有托管类型的函数定义必须具有 __clrcall 调用约定”时遇到了错误。

我在头文件（.h）中的代码是：

extern "C" 
{

__declspec(dllexport) int __stdcall ABC(int i);
__declspec(dllexport) char* __stdcall C(int i);
__declspec(dllexport) array<char>^ __stdcall WrappedC(int i) ;

}

我尝试将 _stdcall 更改为 __clrcall 但又出现另一个错误：

error C3395: 'WrappedC' : __declspec(dllexport) cannot be applied to a function with the __clrcall calling convention

我在网上搜索过，但还没有解决。

谢谢，

大统华集团