Native windows open file dialog

file_dialogs_windows.go

@@ -0,0 +1,71 @@
+package main
+
+import (
+	"fmt"
+	"syscall"
+	"unicode/utf16"
+	"unsafe"
+)
+
+var (
+	comdlg32            = syscall.NewLazyDLL("Comdlg32.dll")
+	procGetOpenFileName = comdlg32.NewProc("GetOpenFileNameW")
+)
+
+var (
+	Err_No_File_Chosen = fmt.Errorf("no file was chosen")
+)
+
+func OpenFileDialog(title string) (filepath string, err error) {
+
+	type OPENFILENAMEW struct {
+		LStructSize   uint32
+		HwndOwner     syscall.Handle
+		HInstance     syscall.Handle
+		Filter        *uint16
+		CustomFilter  *uint16
+		MaxCustFilter uint32
+		FilterIndex   uint32
+		File          *uint16
+		MaxFile       uint32
+		FileTitle     *uint16
+		MaxFileTitle  uint32
+		InitialDir    *uint16
+		Title         *uint16
+		Flags         uint32
+		FileOffset    uint16
+		FileExtension uint16
+		DefExt        *uint16
+		CustData      uintptr
+		FnHook        syscall.Handle
+		TemplateName  *uint16
+		PvReserved    uintptr
+		DwReserved    uint32
+		FlagsEx       uint32
+	}
+
+	titleByteArr := utf16.Encode([]rune(title + "\x00"))
+	filterByteArr := utf16.Encode([]rune("All Files (*.*)\x00*.*\x00Text Files (*.txt)\x00*.txt\x00\x00"))
+
+	filenameByteArr := make([]uint16, syscall.MAX_LONG_PATH)
+
+	ofn := &OPENFILENAMEW{
+		HwndOwner:   0,
+		HInstance:   0,
+		LStructSize: uint32(unsafe.Sizeof(OPENFILENAMEW{})),
+		Title:       &titleByteArr[0],
+		Filter:      &filterByteArr[0],
+		File:        &filenameByteArr[0],
+		MaxFile:     syscall.MAX_LONG_PATH,
+		// OFN_FILEMUSTEXIST
+		Flags: 0x00001000,
+	}
+
+	ret, _, _ := procGetOpenFileName.Call(uintptr(unsafe.Pointer(ofn)))
+	if ret == 0 {
+		return "", Err_No_File_Chosen
+	}
+
+	filepath = syscall.UTF16ToString(filenameByteArr)
+	return filepath, nil
+}