Windows Form WinAPi custom Savefiledialog - Manage lost focus on control edit - winapi

Question

I need to create on my windows form c# application a custom save file dialog.
I'm used this example as starting point
https://www.codeproject.com/Articles/8086/Extending-the-save-file-dialog-class-in-NET
I have modified the code and add 2 edit control for Width and Height.
I'd like that when change text on width and lost focus, the height texbox update value proporzionally,
But I don't kwow how manage lost focus on edit control.
Here my 2 controls:
int textWidthHandle = CreateWindowEx(0, "Edit", width, ES_NUMBER | WS_VISIBLE | WS_CHILD | WS_TABSTOP | WS_BORDER, point.X + 108, point.Y + 8, 47, 20, parent, 0, 0, 0);
SendMessage((int)textWidthHandle, WM_SETFONT, fontHandle, 0);
int textHeightHandle = CreateWindowEx(0, "Edit", height, ES_NUMBER | WS_VISIBLE | WS_CHILD | WS_TABSTOP | WS_BORDER, point.X + 199, point.Y + 8, 47, 20, parent, 0, 0, 0);
SendMessage((int)textHeightHandle, WM_SETFONT, fontHandle, 0);
Can you help me please?
Here my full code:
public enum EncodingType
{
A75 = 0,
A76 = 1,
A77 = 2,
A78 = 3,
A79 = 4,
A80 = 5,
A81 = 6,
A82 = 7,
A83 = 8,
A84 = 9,
A85 = 10,
A86 = 11,
A87 = 12,
A88 = 13,
A89 = 14,
A90 = 15,
A91 = 16,
A92 = 17,
A93 = 18,
A94 = 19,
A95 = 20,
A96 = 21,
A97 = 22,
A98 = 23,
A99 = 24,
A100 = 25,
}
public class SaveFileDialogWithEncoding
{
private delegate int OFNHookProcDelegate(int hdlg, int msg, int wParam, int lParam);
private int m_LabelHandle = 0;
private int m_ComboHandle = 0;
private int m_WidthHandle = 0;
private int m_HeightHandle = 0;
private string m_Filter = "";
private string m_DefaultExt = "";
private string m_FileName = "";
private EncodingType m_EncodingType;
private int m_width;
private int m_height;
private Screen m_ActiveScreen;
[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]
private struct OPENFILENAME
{
public int lStructSize;
public IntPtr hwndOwner;
public int hInstance;
[MarshalAs(UnmanagedType.LPTStr)]
public string lpstrFilter;
[MarshalAs(UnmanagedType.LPTStr)]
public string lpstrCustomFilter;
public int nMaxCustFilter;
public int nFilterIndex;
[MarshalAs(UnmanagedType.LPTStr)]
public string lpstrFile;
public int nMaxFile;
[MarshalAs(UnmanagedType.LPTStr)]
public string lpstrFileTitle;
public int nMaxFileTitle;
[MarshalAs(UnmanagedType.LPTStr)]
public string lpstrInitialDir;
[MarshalAs(UnmanagedType.LPTStr)]
public string lpstrTitle;
public int Flags;
public short nFileOffset;
public short nFileExtension;
[MarshalAs(UnmanagedType.LPTStr)]
public string lpstrDefExt;
public int lCustData;
public OFNHookProcDelegate lpfnHook;
[MarshalAs(UnmanagedType.LPTStr)]
public string lpTemplateName;
//only if on nt 5.0 or higher
public int pvReserved;
public int dwReserved;
public int FlagsEx;
}
[DllImport("Comdlg32.dll", CharSet = CharSet.Auto, SetLastError = true)]
private static extern bool GetSaveFileName(ref OPENFILENAME lpofn);
[DllImport("Comdlg32.dll")]
private static extern int CommDlgExtendedError();
[DllImport("user32.dll")]
private static extern bool SetWindowPos(int hWnd, int hWndInsertAfter, int X, int Y, int cx, int cy, uint uFlags);
private struct RECT
{
public int Left;
public int Top;
public int Right;
public int Bottom;
}
private struct POINT
{
public int X;
public int Y;
}
private struct NMHDR
{
public int HwndFrom;
public int IdFrom;
public int Code;
}
[DllImport("user32.dll")]
private static extern bool GetWindowRect(int hWnd, ref RECT lpRect);
[DllImport("user32.dll")]
private static extern int GetParent(int hWnd);
[DllImport("user32.dll", CharSet = CharSet.Auto)]
private static extern bool SetWindowText(int hWnd, string lpString);
[DllImport("user32.dll", EntryPoint = "SendMessage", CharSet = System.Runtime.InteropServices.CharSet.Auto)]
public static extern bool SendMessage(IntPtr hWnd, uint Msg, int wParam, StringBuilder lParam);
[DllImport("user32.dll")]
private static extern int SendMessage(int hWnd, int Msg, int wParam, int lParam);
[DllImport("user32.dll", CharSet = CharSet.Auto)]
private static extern int SendMessage(int hWnd, int Msg, int wParam, string lParam);
[DllImport("user32.dll")]
private static extern bool DestroyWindow(int hwnd);
private const int OFN_ENABLEHOOK = 0x00000020;
private const int OFN_EXPLORER = 0x00080000;
private const int OFN_FILEMUSTEXIST = 0x00001000;
private const int OFN_HIDEREADONLY = 0x00000004;
private const int OFN_CREATEPROMPT = 0x00002000;
private const int OFN_NOTESTFILECREATE = 0x00010000;
private const int OFN_OVERWRITEPROMPT = 0x00000002;
private const int OFN_PATHMUSTEXIST = 0x00000800;
private const int SWP_NOSIZE = 0x0001;
private const int SWP_NOMOVE = 0x0002;
private const int SWP_NOZORDER = 0x0004;
private const int WM_KILLFOCUS = 0x0008;
private const int WM_INITDIALOG = 0x110;
private const int WM_DESTROY = 0x2;
private const int WM_SETFONT = 0x0030;
private const int WM_GETFONT = 0x0031;
private const int WM_COMMAND = 0x0111;
private const int WM_GETTEXT = 0x000D;
private const int CBS_DROPDOWNLIST = 0x0003;
private const int CBS_HASSTRINGS = 0x0200;
private const int CB_ADDSTRING = 0x0143;
private const int CB_SETCURSEL = 0x014E;
private const int CB_GETCURSEL = 0x0147;
private const uint WS_VISIBLE = 0x10000000;
private const uint WS_CHILD = 0x40000000;
private const uint WS_TABSTOP = 0x00010000;
private const uint WS_BORDER = 0x00800000;
private const int ES_NUMBER = 0x2000;
private const int CDN_FILEOK = -606;
private const int WM_NOTIFY = 0x004E;
private const int WM_KEYDOWN = 0x0100;
[DllImport("user32.dll", CharSet = CharSet.Auto)]
private static extern int GetDlgItem(int hDlg, int nIDDlgItem);
[DllImport("user32.dll", SetLastError = true, CharSet = CharSet.Auto)]
static extern int GetWindowTextLength(IntPtr hWnd);
[DllImport("user32.dll", CharSet = CharSet.Auto)]
private static extern int CreateWindowEx(int dwExStyle, string lpClassName, string lpWindowName, uint dwStyle, int x, int y, int nWidth, int nHeight, int hWndParent, int hMenu, int hInstance, int lpParam);
[DllImport("user32.dll")]
private static extern bool ScreenToClient(int hWnd, ref POINT lpPoint);
private int HookProc(int hdlg, int msg, int wParam, int lParam)
{
switch (msg)
{
case WM_INITDIALOG:
//we need to centre the dialog
Rectangle sr = m_ActiveScreen.Bounds;
RECT cr = new RECT();
int parent = GetParent(hdlg);
GetWindowRect(parent, ref cr);
int x = (sr.Right + sr.Left - (cr.Right - cr.Left)) / 2;
int y = (sr.Bottom + sr.Top - (cr.Bottom - cr.Top)) / 2;
SetWindowPos(parent, 0, x, y, cr.Right - cr.Left, cr.Bottom - cr.Top + 32, SWP_NOZORDER);
//we need to find the label to position our new label under
int fileTypeWindow = GetDlgItem(parent, 0x441);
RECT aboveRect = new RECT();
GetWindowRect(fileTypeWindow, ref aboveRect);
//now convert the label's screen co-ordinates to client co-ordinates
POINT point = new POINT();
point.X = aboveRect.Left;
point.Y = aboveRect.Bottom;
ScreenToClient(parent, ref point);
//create the label
int labelHandle = CreateWindowEx(0, "STATIC", "mylabel", WS_VISIBLE | WS_CHILD | WS_TABSTOP, point.X, point.Y + 16, 200, 100, parent, 0, 0, 0);
SetWindowText(labelHandle, "Jpeg Compression:");
int fontHandle = SendMessage(fileTypeWindow, WM_GETFONT, 0, 0);
SendMessage(labelHandle, WM_SETFONT, fontHandle, 0);
//we now need to find the combo-box to position the new combo-box under
int fileComboWindow = GetDlgItem(parent, 0x470);
aboveRect = new RECT();
GetWindowRect(fileComboWindow, ref aboveRect);
point = new POINT();
point.X = aboveRect.Left;
point.Y = aboveRect.Bottom;
ScreenToClient(parent, ref point);
POINT rightPoint = new POINT();
rightPoint.X = aboveRect.Right;
rightPoint.Y = aboveRect.Top;
ScreenToClient(parent, ref rightPoint);
Form1 f = (Form1)(Application.OpenForms[0]);
//we create the new combobox
int comboHandle = CreateWindowEx(0, "ComboBox", "mycombobox", WS_VISIBLE | WS_CHILD | CBS_HASSTRINGS | CBS_DROPDOWNLIST | WS_TABSTOP, point.X, point.Y + 8, 50, 100, parent, 0, 0, 0);
SendMessage(comboHandle, WM_SETFONT, fontHandle, 0);
//create the label
int labelHandle2 = CreateWindowEx(0, "STATIC", "mylabel2", WS_VISIBLE | WS_CHILD | WS_TABSTOP, point.X + 73, point.Y + 12, 100, 100, parent, 0, 0, 0);
SetWindowText(labelHandle2, "Width:");
SendMessage(labelHandle2, WM_SETFONT, fontHandle, 0);
Size s = f.GetResolution();
string width = s.Width != 0 ? s.Width.ToString() : "";
string height = s.Height != 0 ? s.Height.ToString() : "";
if (s.Width > 0)
m_width = s.Width;
if (s.Height > 0)
m_height = s.Height;
int textWidthHandle = CreateWindowEx(0, "Edit", width, ES_NUMBER | WS_VISIBLE | WS_CHILD | WS_TABSTOP | WS_BORDER, point.X + 108, point.Y + 8, 47, 20, parent, 0, 0, 0);
SendMessage((int)textWidthHandle, WM_SETFONT, fontHandle, 0);
//create the label
int labelHandle3 = CreateWindowEx(0, "STATIC", "mylabel3", WS_VISIBLE | WS_CHILD | WS_TABSTOP, point.X + 162, point.Y + 12, 100, 100, parent, 0, 0, 0);
SetWindowText(labelHandle3, "Height:");
SendMessage(labelHandle3, WM_SETFONT, fontHandle, 0);
int textHeightHandle = CreateWindowEx(0, "Edit", height, ES_NUMBER | WS_VISIBLE | WS_CHILD | WS_TABSTOP | WS_BORDER, point.X + 199, point.Y + 8, 47, 20, parent, 0, 0, 0);
SendMessage((int)textHeightHandle, WM_SETFONT, fontHandle, 0);
//and add the encodings we want to offer
SendMessage(comboHandle, CB_ADDSTRING, 0, "75");
SendMessage(comboHandle, CB_ADDSTRING, 0, "76");
SendMessage(comboHandle, CB_ADDSTRING, 0, "77");
SendMessage(comboHandle, CB_ADDSTRING, 0, "78");
SendMessage(comboHandle, CB_ADDSTRING, 0, "79");
SendMessage(comboHandle, CB_ADDSTRING, 0, "80");
SendMessage(comboHandle, CB_ADDSTRING, 0, "81");
SendMessage(comboHandle, CB_ADDSTRING, 0, "82");
SendMessage(comboHandle, CB_ADDSTRING, 0, "83");
SendMessage(comboHandle, CB_ADDSTRING, 0, "84");
SendMessage(comboHandle, CB_ADDSTRING, 0, "85");
SendMessage(comboHandle, CB_ADDSTRING, 0, "86");
SendMessage(comboHandle, CB_ADDSTRING, 0, "87");
SendMessage(comboHandle, CB_ADDSTRING, 0, "88");
SendMessage(comboHandle, CB_ADDSTRING, 0, "89");
SendMessage(comboHandle, CB_ADDSTRING, 0, "90");
SendMessage(comboHandle, CB_ADDSTRING, 0, "91");
SendMessage(comboHandle, CB_ADDSTRING, 0, "92");
SendMessage(comboHandle, CB_ADDSTRING, 0, "93");
SendMessage(comboHandle, CB_ADDSTRING, 0, "94");
SendMessage(comboHandle, CB_ADDSTRING, 0, "95");
SendMessage(comboHandle, CB_ADDSTRING, 0, "96");
SendMessage(comboHandle, CB_ADDSTRING, 0, "97");
SendMessage(comboHandle, CB_ADDSTRING, 0, "98");
SendMessage(comboHandle, CB_ADDSTRING, 0, "99");
SendMessage(comboHandle, CB_ADDSTRING, 0, "100");
m_EncodingType = EncodingType.A94;
SendMessage(comboHandle, CB_SETCURSEL, (int)m_EncodingType, 0);
//remember the handles of the controls we have created so we can destroy them after
m_LabelHandle = labelHandle;
m_ComboHandle = comboHandle;
m_WidthHandle = textWidthHandle;
m_HeightHandle = textHeightHandle;
break;
case WM_DESTROY:
//destroy the handles we have created
if (m_ComboHandle != 0)
{
DestroyWindow(m_ComboHandle);
}
if (m_WidthHandle != 0)
{
DestroyWindow(m_WidthHandle);
}
if (m_HeightHandle != 0)
{
DestroyWindow(m_HeightHandle);
}
if (m_LabelHandle != 0)
{
DestroyWindow(m_LabelHandle);
}
break;
case WM_NOTIFY:
//we need to intercept the CDN_FILEOK message
//which is sent when the user selects a filename
NMHDR nmhdr = (NMHDR)Marshal.PtrToStructure(new IntPtr(lParam), typeof(NMHDR));
if (nmhdr.Code == CDN_FILEOK)
{
//a file has been selected
//we need to get the encoding
m_EncodingType = (EncodingType)SendMessage(m_ComboHandle, CB_GETCURSEL, 0, 0);
int max_length = GetWindowTextLength((IntPtr)m_WidthHandle);
StringBuilder widthtext = new StringBuilder(max_length + 1);
SendMessage((IntPtr)m_WidthHandle, WM_GETTEXT, widthtext.Capacity, widthtext);
int retWidth;
Int32.TryParse(widthtext.ToString(), out retWidth);
m_width = retWidth;
int max_lengthh = GetWindowTextLength((IntPtr)m_HeightHandle);
StringBuilder heighttext = new StringBuilder(max_lengthh + 1);
SendMessage((IntPtr)m_HeightHandle, WM_GETTEXT, heighttext.Capacity, heighttext);
int retHeight;
Int32.TryParse(heighttext.ToString(), out retHeight);
m_height = retHeight;
}
break;
}
return 0;
}
public string DefaultExt
{
get
{
return m_DefaultExt;
}
set
{
m_DefaultExt = value;
}
}
public string Filter
{
get
{
return m_Filter;
}
set
{
m_Filter = value;
}
}
public string FileName
{
get
{
return m_FileName;
}
set
{
m_FileName = value;
}
}
public EncodingType EncodingType
{
get
{
return m_EncodingType;
}
set
{
m_EncodingType = value;
}
}
public int Width
{
get
{
return m_width;
}
set
{
m_width = value;
}
}
public int Height
{
get
{
return m_height;
}
set
{
m_height = value;
}
}
public DialogResult ShowDialog()
{
//set up the struct and populate it
OPENFILENAME ofn = new OPENFILENAME();
ofn.lStructSize = Marshal.SizeOf(ofn);
ofn.lpstrFilter = m_Filter.Replace('|', '\0') + '\0';
ofn.lpstrFile = m_FileName + new string(' ', 512);
ofn.nMaxFile = ofn.lpstrFile.Length;
ofn.lpstrFileTitle = System.IO.Path.GetFileName(m_FileName) + new string(' ', 512);
ofn.nMaxFileTitle = ofn.lpstrFileTitle.Length;
Form1 f = (Form1)(Application.OpenForms[0]);
RadioButton radioButtonIta = (RadioButton)f.Controls["radioButtonIta"];
if (radioButtonIta.Checked)
{
ofn.lpstrTitle = "Salva immagine come";
}
else
{
ofn.lpstrTitle = "Save image as";
}
ofn.lpstrDefExt = m_DefaultExt;
//position the dialog above the active window
ofn.hwndOwner = Form.ActiveForm.Handle;
//we need to find out the active screen so the dialog box is
//centred on the correct display
m_ActiveScreen = Screen.FromControl(Form.ActiveForm);
//set up some sensible flags
ofn.Flags = OFN_EXPLORER | OFN_PATHMUSTEXIST | OFN_NOTESTFILECREATE | OFN_ENABLEHOOK | OFN_HIDEREADONLY | OFN_OVERWRITEPROMPT;
//this is where the hook is set. Note that we can use a C# delegate in place of a C function pointer
ofn.lpfnHook = new OFNHookProcDelegate(HookProc);
//if we're running on Windows 98/ME then the struct is smaller
if (System.Environment.OSVersion.Platform != PlatformID.Win32NT)
{
ofn.lStructSize -= 12;
}
//show the dialog
if (!GetSaveFileName(ref ofn))
{
int ret = CommDlgExtendedError();
if (ret != 0)
{
throw new ApplicationException("Couldn't show file open dialog - " + ret.ToString());
}
return DialogResult.Cancel;
}
m_FileName = ofn.lpstrFile;
return DialogResult.OK;
}
}
Thanks