CODEWITHSUNDEEP
c#wpfwinformsfileopenpicker
Yuzhe Zhou
Yuzhe Zhou

Reputation: 157

“Invalid window handle” error when using FileOpenPicker from C# .net framwork 4.7.2 with Microsoft.Windows.SDK.Contracts without UWP

I am trying to use Microsoft.Windows.SDK.Contracts to access the Windows10 API from .net framework WFP application. I want to use the FileOpenPicker() to select the image for OCR processing by Windows.Media.Ocr. But I met the 'Invalid window handle' error when using the picker

I found a post which met the similar a link issue with C++/WinRT. One of the answer point out " The program will crash because the File­Open­Picker looks for a Core­Window on the current thread to serve as the owner of the dialog. But we are a Win32 desktop app without a Core­Window." I think the root cause is the same. But I don't know how to fix from the my code based on .net framework side.

public async void Load()
{
    var picker = new FileOpenPicker()
    {
        SuggestedStartLocation = PickerLocationId.PicturesLibrary,
        FileTypeFilter = { ".jpg", ".jpeg", ".png", ".bmp" },
    };

    var file = await picker.PickSingleFileAsync();
    if (file != null)
    {

    }
    else
    {

    }
}

Error message: System.Exception: 'Invalid window handle.(Exception from HRESULT:0x80070578)'

Upvotes: 7

Views: 5063

Answers (2)

Shengjie Lu
Shengjie Lu

Reputation: 1

Similar to @Cataurus !! bind handler with picker !!

private async void Button_Click_Choose_Left_Folder(object sender, RoutedEventArgs e)
{
var folderPicker = new FolderPicker();

// 获取当前窗口的句柄（在 WinUI 或桌面应用中）
IntPtr hwnd = System.Diagnostics.Process.GetCurrentProcess().MainWindowHandle;

// 将文件夹选择器与窗口句柄关联
WinRT.Interop.InitializeWithWindow.Initialize(folderPicker, hwnd);

folderPicker.SuggestedStartLocation = PickerLocationId.PicturesLibrary;
...

var folder = await folderPicker.PickSingleFolderAsync();
}

Upvotes: 0

Cataurus
Cataurus

Reputation: 78

Create a file with:

using System;
using System.Runtime.InteropServices;

namespace <standardnamespace>
{
    [ComImport]
    [Guid("3E68D4BD-7135-4D10-8018-9FB6D9F33FA1")]
    [InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
    public interface IInitializeWithWindow
    {
        void Initialize(IntPtr hwnd);
    }
}

change your code to:

public async void Load()
{
    var picker = new FileOpenPicker()
    {
        SuggestedStartLocation = PickerLocationId.PicturesLibrary,
        FileTypeFilter = { ".jpg", ".jpeg", ".png", ".bmp" },
    };

    ((IInitializeWithWindow)(object)picker).Initialize(System.Diagnostics.Process.GetCurrentProcess().MainWindowHandle);    

    var file = await picker.PickSingleFileAsync();
    if (file != null)
    {

    }
    else
    {

    }
}

Upvotes: 6

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