如何将图像直接从相机或智能手机拖到 C# 应用程序？答案

【问题标题】：How To drag images directly from Camera or Smartphone to C# app?如何将图像直接从相机或智能手机拖到 C# 应用程序？
【发布时间】：2015-06-10 14:51:21
【问题描述】：

我找到了一个脚本 (http://www.codeproject.com/Articles/28209/Outlook-Drag-and-Drop-in-C)，它可以将图像拖到 c# 应用程序中。（尤其是来自 Outlook） fileDrop 格式用于将图像从我的硬盘复制（拖动）到 c# 应用程序。这在图像存储在我的硬盘上时效果很好，但是当我尝试直接从我的存储卡（从相机或智能手机（如三星 S3）中）拖动图像时，它就不起作用了。这些是我从这些图像中获得的拖动格式：

(0): "Shell IDList Array"
(1): "FileContents"
(2): "FileGroupDescriptorW"
(3): "WPD Storage Attributes"
(4): "Preferred DropEffect"
(5): "WPD NSE"
(6): "WPD NSE PnPDevicePath"
(7): "WPD NSE StoragePUID"
(8): "UsingDefaultDragImage"
(9): "DragImageBits"
(10): "DragContext"
(11): "DragSourceHelperFlags"
(12): "InShellDragLoop"
(13): "IsShowingLayered"
(14): "DragWindow"
(15): "IsComputingImage"
(16): "DataObjectAttributes"
(17): "DisableDragText"
(18): "IsShowingText"
(19): "DropDescription"
(20): "ComputedDragImage"
(21): "Logical Performed DropEffect"
(22): "Performed DropEffect"
(23): "Paste Succeeded"

当我尝试访问“FileGroupDescriptorW”时，我收到了非法访问冲突错误。另外，这里似乎缺少“FileGroupDescriptor”？谁能帮我解决这个问题？我搜索了这个网站和谷歌，但没有找到任何有用的东西。

【问题讨论】：

标签： c# image winforms drag sd-card

【解决方案1】：

解决方案由 John Schroedl 发布，并隐藏在该主题的许多反应中。

这两个“修复”解决了我的问题：

http://www.codeproject.com/Articles/28209/Outlook-Drag-and-Drop-in-C?msg=3535951#xx3535951xx

旧 C#：

[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Ansi)]
public sealed class FILEGROUPDESCRIPTORA
{
    public uint cItems;
    public FILEDESCRIPTORA[] fgd;
}

[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)]
public sealed class FILEGROUPDESCRIPTORW
{
    public uint cItems;
    public FILEDESCRIPTORW[] fgd;
}

固定 C#：

[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Ansi)]
public sealed class FILEGROUPDESCRIPTORA
{
    public uint cItems;
    public FILEDESCRIPTORA fgd;
}

[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)]
public sealed class FILEGROUPDESCRIPTORW
{
    public uint cItems;
    public FILEDESCRIPTORW fgd;
}

这个修复：http://www.codeproject.com/Articles/28209/Outlook-Drag-and-Drop-in-C?msg=3551197#xx3551197xx

旧：

case "FileContents":
    //override the default handling of FileContents which returns the
    //contents of the first file as a memory stream and instead return
    //a array of MemoryStreams containing the data to each file dropped

    //get the array of filenames which lets us know how many file contents exist
    string[] fileContentNames = (string[])this.GetData("FileGroupDescriptor");

修复：

case "FileContents":
    //override the default handling of FileContents which returns the
    //contents of the first file as a memory stream and instead return
    //a array of MemoryStreams containing the data to each file dropped
    //
    // FILECONTENTS requires a companion FILEGROUPDESCRIPTOR to be
    // available so we bail out if we don't find one in the data object.

    string fgdFormatName;

    if (GetDataPresent("FileGroupDescriptorW"))
        fgdFormatName = "FileGroupDescriptorW";
    else if (GetDataPresent("FileGroupDescriptor"))
        fgdFormatName = "FileGroupDescriptor";
    else
        return null;

    //get the array of filenames which lets us know how many file contents exist
    string[] fileContentNames = (string[])this.GetData(fgdFormatName);

万一有人需要...

【讨论】：