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How to get the windows messages according to the child?

I am creating a form inside another form. In the child form I have created taskbar button. I am overriding WndProc in the button.I am referring https://www.codeproject.com/Articles/10171/Adding-a-Minimize-to-tray-button-to-a-Form-s-caption bar. But whenever I am getting messages(mouse coordinates) , it is given with respect to the parent form. This makes trouble in calculations .I want those with respect to child form.How to achieve this?
This is the code for form1
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
Form2 form2 = new Form2();
form2.TopLevel = false;
form2.AutoScroll = true;
form2.Anchor = AnchorStyles.Top;
form2.Dock = DockStyle.Fill;
this.splitContainer1.Panel2.Controls.Add(form2);
form2.Show();
}
}
this is form2.
public partial class Form2 : Form
{
TyronM.MinTrayBtn Pin_Button;
public Form2()
{
InitializeComponent();
Pin_Button = new TyronM.MinTrayBtn(this);
Pin_Button.MinTrayBtnClicked += new TyronM.MinTrayBtnClickedEventHandler(this.Pin_Button_Clicked);
}
public void Pin_Button_Clicked(object sender, EventArgs e)
{
MessageBox.Show("Pin button got Clicked");
}
protected override void WndProc(ref Message message)
{
const int WM_SYSCOMMAND = 0x0112;
const int SC_MOVE = 0xF010;
switch (message.Msg)
{
case WM_SYSCOMMAND:
int command = message.WParam.ToInt32() & 0xfff0;
if (command == SC_MOVE)
return;
break;
}
base.WndProc(ref message);
}
}
And this is for button.
using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;
using System.Diagnostics;
using System.Resources;
using System.Runtime.InteropServices;
namespace TyronM {
public delegate void MinTrayBtnClickedEventHandler(object sender, EventArgs e);
/// <summary>
/// Summary description for Class.
/// </summary>
public class MinTrayBtn : NativeWindow {
bool pinned = false;
bool pressed = false;
Size wnd_size = new Size();
public bool captured;
Form parent;
public event MinTrayBtnClickedEventHandler MinTrayBtnClicked;
#region Constants
const int WM_SIZE = 5;
const int WM_SYNCPAINT = 136;
const int WM_MOVE = 3;
const int WM_ACTIVATE = 6;
const int WM_LBUTTONDOWN =513;
const int WM_LBUTTONUP =514;
const int WM_LBUTTONDBLCLK =515;
const int WM_MOUSEMOVE = 512;
const int WM_PAINT = 15;
const int WM_GETTEXT = 13;
const int WM_NCCREATE =129;
const int WM_NCLBUTTONDOWN = 161;
const int WM_NCLBUTTONUP = 162;
const int WM_NCMOUSEMOVE = 160;
const int WM_NCACTIVATE =134;
const int WM_NCPAINT = 133;
const int WM_NCHITTEST = 132;
const int WM_NCLBUTTONDBLCLK = 163;
const int VK_LBUTTON = 1;
const int SM_CXSIZE = 30;
const int SM_CYSIZE = 31;
#endregion
#region Extra Constants
const int WM_MBUTTONUP = 0x0208;
#endregion
#region WinAPI Imports
[DllImport("user32")]
public static extern int GetWindowDC(int hwnd);
[DllImport("user32")]
public static extern short GetAsyncKeyState(int vKey);
[DllImport("user32")]
public static extern int SetCapture(int hwnd);
[DllImport("user32")]
public static extern bool ReleaseCapture();
[DllImport("user32")]
public static extern int GetSysColor(int nIndex);
[DllImport("user32")]
public static extern int GetSystemMetrics(int nIndex);
#endregion
#region Constructor and Handle-Handler ^^
public MinTrayBtn(Form parent) {
parent.HandleCreated += new EventHandler(this.OnHandleCreated);
parent.HandleDestroyed+= new EventHandler(this.OnHandleDestroyed);
parent.TextChanged+= new EventHandler(this.OnTextChanged);
this.parent = parent;
}
// Listen for the control's window creation and then hook into it.
internal void OnHandleCreated(object sender, EventArgs e){
// Window is now created, assign handle to NativeWindow.
AssignHandle(((Form)sender).Handle);
}
internal void OnHandleDestroyed(object sender, EventArgs e) {
// Window was destroyed, release hook.
ReleaseHandle();
}
// Changing the Text invalidates the Window, so we got to Draw the Button again
private void OnTextChanged(object sender, EventArgs e) {
DrawButton();
}
#endregion
#region WndProc
[System.Security.Permissions.PermissionSet(System.Security.Permissions.SecurityAction.Demand, Name="FullTrust")]
protected override void WndProc(ref Message m){
//label3.Text = "Button pressed: " + pressed;
//label4.Text = "Mouse captured: " + captured;
// Change the Pressed-State of the Button when the User pressed the
// left mouse button and moves the cursor over the button
if (m.Msg == WM_LBUTTONDBLCLK ||m.Msg == WM_LBUTTONDOWN || m.Msg == WM_LBUTTONUP
||m.Msg == WM_MBUTTONUP
)
MessageBox.Show("click happened");
if(m.Msg==WM_MOUSEMOVE) {
Point pnt2 = new Point((int)m.LParam);
Size rel_pos2 = new Size(parent.PointToClient(new Point(parent.Location.X, parent.Location.Y)));
// Not needed because SetCapture seems to convert the cordinates anyway
//pnt2 = PointToClient(pnt2);
pnt2-=rel_pos2;
//label2.Text = "Cursor #"+pnt2.X+"/"+pnt2.Y;
if(pressed) {
Point pnt = new Point((int)m.LParam);
Size rel_pos = new Size(parent.PointToClient(new Point(parent.Location.X, parent.Location.Y)));
//pnt = PointToClient(pnt);
pnt-=rel_pos;
if(!MouseinBtn(pnt)) {
pressed = false;
DrawButton();
}
} else {
if((GetAsyncKeyState(VK_LBUTTON)&(-32768))!=0) {
Point pnt = new Point((int)m.LParam);
Size rel_pos = new Size(parent.PointToClient(new Point(parent.Location.X, parent.Location.Y)));
//pnt = PointToClient(pnt);
pnt-=rel_pos;
if(MouseinBtn(pnt)) {
pressed = true;
DrawButton();
}
}
}
}
// Ignore Double-Clicks on the Traybutton
if(m.Msg==WM_NCLBUTTONDBLCLK) {
Point pnt = new Point((int)m.LParam);
Size rel_pos = new Size(parent.PointToClient(new Point(parent.Location.X, parent.Location.Y)));
pnt = parent.PointToClient(pnt);
pnt-=rel_pos;
if(MouseinBtn(pnt)) {
return;
}
}
#region NOT WORKING
// Button released and eventually clicked
if(m.Msg==WM_LBUTTONUP)
{
ReleaseCapture();
captured = false;
if(pressed) {
pressed = false;
DrawButton();
Point pnt = new Point((int)m.LParam);
Size rel_pos = new Size(parent.PointToClient(new Point(parent.Location.X, parent.Location.Y)));
pnt-=rel_pos;
if(MouseinBtn(pnt)) {
//TrayButton_clicked();
EventArgs e = new EventArgs();
if (MinTrayBtnClicked != null)
MinTrayBtnClicked(this, e);
return;
}
}
}
#endregion
// Clicking the Button - Capture the Mouse and await until the Uses relases the Button again
if(m.Msg==WM_NCLBUTTONDOWN) {
//MessageBox.Show("clicked");
Point pnt = new Point((int)m.LParam);
Size rel_pos = new Size(parent.PointToClient(new Point(parent.Location.X, parent.Location.Y)));
pnt = parent.PointToClient(pnt);
pnt-=rel_pos;
if(MouseinBtn(pnt)) {
MessageBox.Show("clicked");
pressed = true;
DrawButton();
SetCapture((int)parent.Handle);
captured = true;
return;
}
}
// Drawing the Button and getting the Real Size of the Window
if(m.Msg == WM_ACTIVATE || m.Msg==WM_SIZE || m.Msg==WM_SYNCPAINT || m.Msg==WM_NCACTIVATE || m.Msg==WM_NCCREATE || m.Msg==WM_NCPAINT || m.Msg==WM_NCACTIVATE || m.Msg==WM_NCHITTEST || m.Msg==WM_PAINT) {
if(m.Msg==WM_SIZE) wnd_size = new Size(new Point((int)m.LParam));
DrawButton();
}
base.WndProc(ref m);
}
#endregion
#region Button-Specific Functions
public bool MouseinBtn(Point click) {
int btn_width = GetSystemMetrics(SM_CXSIZE);
int btn_height = GetSystemMetrics(SM_CYSIZE);
Size btn_size = new Size(btn_width, btn_height);
Point pos = new Point(wnd_size.Width - 3 * btn_width - 12 - (btn_width - 18)+7, 6+4);
return click.X>=pos.X && click.X<=pos.X+btn_size.Width &&
click.Y>=pos.Y && click.Y<=pos.Y+btn_size.Height;
}
public void DrawButton() {
Graphics g = Graphics.FromHdc((IntPtr)GetWindowDC((int)parent.Handle)); //m.HWnd));
DrawButton(g, pressed);
}
public void DrawButton(Graphics g, bool pressed) {
int btn_width = GetSystemMetrics(SM_CXSIZE);
int btn_height = GetSystemMetrics(SM_CYSIZE);
//Point pos = new Point(wnd_size.Width-3*btn_width-12-(btn_width-18),6);
Point pos = new Point(wnd_size.Width - 3 * btn_width - 12 - (btn_width - 18)+7, 6+4);
// real button size
btn_width-=2;
btn_height-=4;
Color light = SystemColors.ControlLightLight;
Color icon = SystemColors.ControlText;
Color background = SystemColors.Control;
Color shadow1 = SystemColors.ControlDark;
Color shadow2 = SystemColors.ControlDarkDark;
Color tmp1, tmp2;
if(pressed) {
tmp1 = shadow2;
tmp2 = light;
} else {
tmp1 = light;
tmp2 = shadow2;
}
g.DrawLine(new Pen(tmp1),pos, new Point(pos.X+btn_width-1,pos.Y));
g.DrawLine(new Pen(tmp1),pos, new Point(pos.X,pos.Y+btn_height-1));
if(pressed) {
g.DrawLine(new Pen(shadow1),pos.X+1, pos.Y+1, pos.X+btn_width-2, pos.Y+1);
g.DrawLine(new Pen(shadow1),pos.X+1, pos.Y+1, pos.X+1, pos.Y+btn_height-2);
} else {
g.DrawLine(new Pen(shadow1),pos.X+btn_width-2, pos.Y+1, pos.X+btn_width-2, pos.Y+btn_height-2);
g.DrawLine(new Pen(shadow1),pos.X+1, pos.Y+btn_height-2, pos.X+btn_width-2, pos.Y+btn_height-2);
}
g.DrawLine(new Pen(tmp2),pos.X+btn_width-1, pos.Y+0, pos.X+btn_width-1, pos.Y+btn_height-1);
g.DrawLine(new Pen(tmp2),pos.X+0, pos.Y+btn_height-1, pos.X+btn_width-1, pos.Y+btn_height-1);
g.FillRectangle(new SolidBrush(background),pos.X+1+Convert.ToInt32(pressed), pos.Y+1+Convert.ToInt32(pressed), btn_width-3,btn_height-3);
#region Added Code
g.FillRectangle(new SolidBrush(icon),pos.X+(float)0.5625*btn_width+Convert.ToInt32(pressed),pos.Y+(float)0.6428*btn_height+Convert.ToInt32(pressed),btn_width*(float)0.1875,btn_height*(float)0.143);
g.DrawImage(Image.FromFile("red_Pushpin.jfif"),new Rectangle( pos,new Size(btn_width,btn_height)));
#endregion
}
#endregion
}
}
This is code for main
static class Program
{
/// <summary>
/// The main entry point for the application.
/// </summary>
[STAThread]
static void Main()
{
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
Application.Run(new Form1());
}
}
This is the screenshot of the winform.
EDIT:
Upon investigation I found that WM_LBUTTONUP(Mouse left button up) is not triggered. Or it is not coming inside WndProc.
EDIT1:
It seems there was a problem in brackets.I changed the if conditions into switch case. This somewhat cleared the "Mouse left button up" problem. Now it is properly triggering. The remaining problem is mouse points based on parent form.

Inserting a control into another control at specific location?

I am working with win forms. I have two forms : my main form, Form1 and a Form I made called TextBlock. I am making a text editor, where you can place text boxes around a page, and edit them (think word).
Here are my two forms.
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void saveToolStripMenuItem_Click(object sender, EventArgs e)
{
saveFileDialog.Filter = "Text File|*.txt";
var result = saveFileDialog.ShowDialog();
if (result == DialogResult.OK)
{
StreamWriter writer = new
StreamWriter(saveFileDialog.OpenFile());
writer.Write(tb_Main.Text);
writer.Dispose();
writer.Close();
}
}
private void panel1_Paint(object sender, PaintEventArgs e)
{
}
private void button_tb_Click(object sender, EventArgs e)
{
TextBlock tb_edit = new TextBlock();
tb_edit.Text = "New Text Block";
// tb_edit.Multiline = true;
// tb_edit.Size = new Size(100,100);
// tb_edit.MinimumSize = new Size(50, 50);
tb_edit.form1 = this;
tb_edit.TopLevel = false;
tb_edit.btn_accepttb.BringToFront();
tb_Main.Controls.Add(tb_edit);
tb_edit.Show();
tb_edit.BringToFront();
}
}
and my custom form here:
public partial class TextBlock : Form
{
public Form1 form1;
public TextBlock()
{
InitializeComponent();
}
private void btn_accepttb_Click(object sender, EventArgs e)
{
TextBox tb_edit = new TextBox();
tb_edit.Text = "New Text Block";
tb_edit.Multiline = true;
tb_edit.Size = this.Size;
int dif = form1.tb_Main.Lines.Count()*(int)tb_edit.Font.Size;
Point loca = new Point(this.Location.X,this.Location.Y+dif);
tb_edit.Location = this.Location;
form1.tb_Main.Controls.Add(tb_edit);
tb_edit.Show();
tb_edit.BringToFront();
form1.tb_Main.Controls.Remove(this);
}
}
What it does: it makes a copy my TextBlock, for placement and resizing purposes. when you have it where you want and how big you want, you click the button, and it replaces itself with a regular textbox, of that size, in that position.
What I want it to do: currently it is working with one exception. I am adding it to the controls, of tb_Main (my main textbox, it takes up the whole form) in Form1, it shows up. its the right size, except when i fill tb_Main with text, and i scroll, the new textbox stays where it is while its parent scrolls behind it.
Question : if I scroll down into my document and decide I want this textbox here, how do I ensure its position relative to the scroll of the textbox im putting it in. so when I scroll on, it basically stays embedded in the page where I put it (when I say "page" im referring to my tb_Main).

It is better to create a richtextbox instead of textbox. It has all capabilities of textbox and way more. This example works only with a richtextbox.
Subclassed richtextbox:
class MyRichTextBox : RichTextBox {
[DllImport( "user32.dll" )]
private static extern bool GetScrollInfo( IntPtr hwnd, SBOrientation fnBar,
ref SCROLLINFO lpsi );
[StructLayout( LayoutKind.Sequential )]
private struct SCROLLINFO {
public uint cbSize;
public ScrollInfoMask fMask;
public int nMin;
public int nMax;
public uint nPage;
public int nPos;
public int nTrackPos;
}
private enum ScrollInfoMask : uint {
SIF_RANGE = 0x1,
SIF_PAGE = 0x2,
SIF_POS = 0x4,
SIF_DISABLENOSCROLL = 0x8,
SIF_TRACKPOS = 0x10,
SIF_ALL = ( SIF_RANGE | SIF_PAGE | SIF_POS | SIF_TRACKPOS ),
}
private enum SBOrientation : int {
SB_HORZ = 0x0,
SB_VERT = 0x1,
}
private const int WM_VSCROLL = 0x115;
private const int SB_LINEUP = 0;
private const int SB_LINEDOWN = 1;
private const int SB_PAGEUP = 2;
private const int SB_PAGEDOWN = 3;
private const int SB_THUMBPOSITION = 4;
private const int SB_THUMBTRACK = 5;
private const int SB_TOP = 6;
private const int SB_BOTTOM = 7;
private const int SB_ENDSCROLL = 8;
private bool isThumbTrack = false;
private TextBox childTextbox = null;
private int scrollPos = 0;
public MyTextBox( TextBox textbox ) { //here you pass the child textbox you want to scroll
childTextbox = textbox;
}
protected override void OnVScroll( EventArgs e ) {
if( childTextbox == null ) { base.OnVScroll( e ); return; }
SCROLLINFO si = new SCROLLINFO();
si.cbSize = (uint)Marshal.SizeOf( si );
si.fMask = ScrollInfoMask.SIF_ALL;
GetScrollInfo( this.Handle, SBOrientation.SB_VERT, ref si );
//there is a difference when the user uses the thumb to get scroll pos.
//When user uses the thumb we get *nTrackPos* otherwise *nPos*
if( isThumbTrack == true ) {
childTextbox.Location = new Point( childTextbox.Location.X, childTextbox.Location.Y -
(si.nTrackPos - scrollPos ) );
isThumbTrack = false;
scrollPos = si.nTrackPos;
}
else {
childTextbox.Location = new Point( childTextbox.Location.X, childTextbox.Location.Y -
( si.nPos - scrollPos ) );
scrollPos = si.nPos;
}
base.OnVScroll( e );
}
protected override void WndProc( ref Message m ) {
int wParam;
if(m.Msg == WM_VSCROLL ) {
wParam = m.WParam.ToInt32();
wParam &= 0xFFFF; //get low 16 bits of wParam
//Check if user is using the thumb to scroll
if( wParam == SB_THUMBTRACK ) {
isThumbTrack = true;
}
}
base.WndProc( ref m );
}
}

ComboBox Text Align Vertically Center

I created the custom combobox on .net framework 1.1, i can custom draw dropdown items, but i can't set or draw the combobox text on Middle Left , combobox text always render top left , but i need text should be render on middle left.
[ToolboxBitmap(typeof(ComboBox))]
public class MenComboBox :ComboBox
{
private Image _image = Image.FromFile("Expand.png");
public MenComboBox()
{
this.DrawMode = DrawMode.OwnerDrawFixed;
this.BackColor = Color.White;
this.ItemHeight = 18;
this.Font = new Font("Arial",12f,FontStyle.Regular);
}
protected override void OnDrawItem(DrawItemEventArgs e)
{
if (!DesignMode)
{
if (e.Index > -1)
{
int textHeight = (int)e.Graphics.MeasureString(this.Items[e.Index].ToString(), e.Font).Height;
Point textPos = new Point(e.Bounds.X + 4, e.Bounds.Y + ((this.ItemHeight - textHeight) / 2));
if ((e.State & DrawItemState.Selected) == DrawItemState.Selected)
{
e.Graphics.FillRectangle(Brushes.Blue, e.Bounds);
e.Graphics.DrawString(this.Items[e.Index].ToString(),e.Font,Brushes.White,textPos);
}
else
{
e.Graphics.FillRectangle(Brushes.White, e.Bounds);
e.Graphics.DrawString(this.Items[e.Index].ToString(),e.Font,Brushes.Black,textPos);
}
}
}
}
protected override void WndProc(ref Message m)
{
base.WndProc(ref m);
if (m.Msg == 0x000F)
{
using (Graphics g = this.CreateGraphics())
{
g.FillRectangle(new SolidBrush(BackColor), this.ClientRectangle);
g.DrawRectangle(Pens.Blue, new Rectangle(this.ClientRectangle.X, this.ClientRectangle.Y, this.ClientRectangle.Width - 1, this.ClientRectangle.Height - 1));
Rectangle rect = new Rectangle(this.Width - 15, 3, 12, this.Height - 6);
g.FillRectangle(new SolidBrush(BackColor), rect);
g.DrawImage(this._image, this.Width - 16, (this.Height - 8) / 2);
g.Dispose();
}
}
}
}

In an owner draw ComboBox the text of the Edit part of the control will always be shown at top left, regardless of the height of the ItemHeight.
To position the Edit part vertically in middle, you can find the Edit element using GetComboBoxInfo and then using SetWindowPos set a new position for it to stand vertically in middle of the ComboBox.
You need to reposition it when the control size changes. Also you need to fill the background of ComboBox with a Color.
Here is the code that I used:
using System;
using System.Drawing;
using System.Runtime.InteropServices;
using System.Windows.Forms;
public class MyComboBox : ComboBox
{
public MyComboBox()
{
SetStyle(ControlStyles.ResizeRedraw, true);
DrawMode = DrawMode.OwnerDrawFixed;
ItemHeight = 40;
}
[StructLayout(LayoutKind.Sequential)]
public struct RECT
{
public int Left;
public int Top;
public int Right;
public int Bottom;
public int Width { get { return Right - Left; } }
public int Height { get { return Bottom - Top; } }
}
private const int SWP_NOSIZE = 0x0001;
private const int SWP_NOZORDER = 0x0004;
private const int SWP_SHOWWINDOW = 0x0040;
[DllImport("user32.dll", SetLastError = true)]
static extern bool SetWindowPos(IntPtr hWnd, IntPtr hWndInsertAfter,
int X, int Y, int cx, int cy, int uFlags);
[DllImport("user32.dll")]
public static extern bool GetComboBoxInfo(IntPtr hWnd, ref COMBOBOXINFO pcbi);
[StructLayout(LayoutKind.Sequential)]
public struct COMBOBOXINFO
{
public int cbSize;
public RECT rcItem;
public RECT rcButton;
public int stateButton;
public IntPtr hwndCombo;
public IntPtr hwndEdit;
public IntPtr hwndList;
}
protected override void OnResize(EventArgs e)
{
base.OnResize(e);
SetupEdit();
Invalidate();
}
private int buttonWidth = SystemInformation.HorizontalScrollBarArrowWidth;
protected override void WndProc(ref Message m)
{
if (m.Msg == 0xF)
{
using (var g = this.CreateGraphics())
{
var r = new Rectangle(2, 2,
ClientRectangle.Width - buttonWidth - 2,
ClientRectangle.Height - 4);
g.FillRectangle(Brushes.White, r);
}
}
base.WndProc(ref m);
}
protected override void OnVisibleChanged(EventArgs e)
{
base.OnVisibleChanged(e);
SetupEdit();
}
private void SetupEdit()
{
var info = new COMBOBOXINFO();
info.cbSize = Marshal.SizeOf(info);
GetComboBoxInfo(this.Handle, ref info);
SetWindowPos(info.hwndEdit, IntPtr.Zero, 3,
(this.Height - Font.Height) / 2,
ClientRectangle.Width - buttonWidth - 3,
ClientRectangle.Height - Font.Height - 4,
SWP_NOZORDER);
}
protected override void OnDrawItem(DrawItemEventArgs e)
{
base.OnDrawItem(e);
e.DrawBackground();
var txt = "";
if (e.Index >= 0)
txt = GetItemText(Items[e.Index]);
TextRenderer.DrawText(e.Graphics, txt, Font, e.Bounds,
ForeColor, TextFormatFlags.Left | TextFormatFlags.VerticalCenter);
}
}

ok, below code doesn't answer the actual question about the Text portion; Hans got it right, as usual.
I keep the answer because I think it does a few things better than OP code..
if (!DesignMode)
{
if (e.Index > -1)
{
using (StringFormat fmt = new StringFormat()
{ Alignment = StringAlignment.Center, LineAlignment = StringAlignment.Center })
{
if ((e.State & DrawItemState.Selected) == DrawItemState.Selected)
{
e.Graphics.FillRectangle(SystemBrushes.MenuHighlight, e.Bounds);
e.Graphics.DrawString(comboBox1.Items[e.Index].ToString(),
e.Font,SystemBrushes.HighlightText, e.Bounds, fmt);
}
else
{
e.Graphics.FillRectangle(SystemBrushes.Window, e.Bounds);
e.Graphics.DrawString(comboBox1.Items[e.Index].ToString(),
e.Font, SystemBrushes.MenuText,e.Bounds, fmt);
}
}
}
}
Instead of calculating a centered position I use the DrawString overload that takes a target rectangle and add a StringFormat to center in both directions. StringFormat was available since .Net 1.1 and indeed is IDisposable, so we should dipose of each we create, best in a using clause..
Note that for drawing controls the use of TextRenderer is encouraged but only came with .Net 2.0.
Also note that I substituted the Brushes for SystemBrushes..
Also: My ComboBox doesn't place the text in its Text portion top-left but middle-left. Maybe the old .Net1.1 control is the culprit?

Drawing lines behind textbox C#

I am working on creating a simple notebook application. I have been asked to make the input area look like a sheet of notebook paper, with the text sitting on light blue lines. I am trying to make this work, but it seems to be failing miserably.
So far, I have created a transparent RichTextBox that sits on top of a panel. The Text Box is:
using System;
using System.Windows.Forms;
public class TransparentTextBox : RichTextBox
{
public TransparentTextBox()
{
this.SetStyle(ControlStyles.Opaque, true);
this.SetStyle(ControlStyles.OptimizedDoubleBuffer, false);
}
protected override CreateParams CreateParams
{
get
{
CreateParams parms = base.CreateParams;
parms.ExStyle |= 0x20; // Turn on WS_EX_TRANSPARENT
return parms;
}
}
}
The paint code for the panel:
private void paper_Paint(object sender, PaintEventArgs e)
{
Graphics g = e.Graphics;
g.Clear(Color.White);
g.DrawLine(new Pen(Brushes.LightPink, 2), 20, 0, 20, paper.Height);
int h = TextRenderer.MeasureText("Testj", txtBody.Font).Height;
for (int x = 2 + h; x < paper.Height; x += h)
{
g.DrawLine(new Pen(Brushes.LightSkyBlue, 2), 0, x, paper.Width, x);
}
}
The lines are static, and they will grow to fit any font size/family that is chosen. The problem is when the text box is scrolled. The lines won't move with the text. I have tried to link the handle of the scroll bar to the lines, but they don't seem to be linking properly.
The code to get the current scroll position:
[StructLayout(LayoutKind.Sequential)]
public struct SCROLLINFO
{
public int cbSize;
public uint fMask;
public int nMin;
public int nMax;
public uint nPage;
public int nPos;
public int nTrackPos;
}
public enum ScrollBarDirection
{
SB_HORZ = 0,
SB_VERT = 1,
SB_CTL = 2,
SB_BOTH = 3
}
public enum ScrollInfoMask
{
SIF_RANGE = 0x1,
SIF_PAGE = 0x2,
SIF_POS = 0x4,
SIF_DISABLENOSCROLL = 0x8,
SIF_TRACKPOS = 0x10,
SIF_ALL = SIF_RANGE + SIF_PAGE + SIF_POS + SIF_TRACKPOS
}
...
public partial class Form1 : Form
{
[DllImport("User32.dll", EntryPoint = "GetScrollInfo")]
[return: MarshalAs(UnmanagedType.Bool)]
private static extern bool GetScrollInfo([In]IntPtr hwnd, [In]int fnBar, [In, Out]ref SCROLLINFO lpsi);
...
private void txtBody_VScroll(object sender, EventArgs e)
{
inf.cbSize = Marshal.SizeOf(inf);
inf.fMask = (int)ScrollInfoMask.SIF_ALL;
GetScrollInfo(txtBody.Handle, 1, ref inf);
Console.WriteLine(inf.nTrackPos + ":" + inf.nPos + ":" + TextRenderer.MeasureText("Testj", txtBody.Font).Height);
paper.Invalidate();
}
Then the paint above was modified to use this:
for (int x = inf.nPos % h; x < paper.Height; x += h)
{
g.DrawLine(new Pen(Brushes.LightSkyBlue, 2), 0, x, paper.Width, x);
}
I also tried to use nTrackPos, but neither seemed to follow the text like I want it to. I'm not too familiar with C#, so I wanted to know what I am missing/could do better. I am using Visual Studio 2008, with Visual C# 2008. .Net framework 3.5 SP1

So, here is what I came up with after some intensive googling. I decided to follow more into Gusman's comment on my question and look into drawing on the textbox again. After some playing, I realized I was improperly calculating the position of the start line. So, I reconfigured my custom RichTextBox to look like:
using System;
using System.Drawing;
using System.Windows.Forms;
using System.Runtime.InteropServices;
namespace Journal
{
class CustomRichTextBox : RichTextBox
{
private const int WM_HSCROLL = 0x114;
private const int WM_VSCROLL = 0x115;
private const int WM_MOUSEWHEEL = 0x20A;
private const int WM_PAINT = 0x00F;
private const int EM_GETSCROLLPOS = 0x4DD;
public int lineOffset = 0;
[DllImport("user32.dll")]
public static extern int SendMessage(
IntPtr hWnd,
int Msg,
IntPtr wParam,
ref Point lParam
);
protected override void WndProc(ref Message m)
{
base.WndProc(ref m);
if (m.Msg == WM_PAINT)
{
using (Graphics g = base.CreateGraphics())
{
Point p = new Point();
//get the position of the scrollbar to calculate the offset
SendMessage(this.Handle, EM_GETSCROLLPOS, IntPtr.Zero, ref p);
//draw the pink line on the side
g.DrawLine(new Pen(Brushes.LightPink, 2), 0, 0, 0, this.Height);
//determine how tall the text will be per line
int h = TextRenderer.MeasureText("Testj", this.Font).Height;
//calculate where the lines need to start
lineOffset = h - (p.Y % h);
//draw lines until there is no more box
for (int x = lineOffset; x < Height; x += h)
{
g.DrawLine(new Pen(Brushes.LightSkyBlue, 2), 0, x, Width, x);
}
//force the panel under us to draw itself.
Parent.Invalidate();
}
}
}
public CustomRichTextBox()
{
this.SetStyle(ControlStyles.OptimizedDoubleBuffer, true);
}
}
}
I then set this box inside of a panel to get the padding I want. The panel is forced to redraw itself with the text box.

disable scrolling in RichTextBox (c#)

I wrote code to display the text in separate pages, like Microsoft Word, I use a Collection of text boxes, and when the user filled one text box, new box is displayed automatically, and the cursor moves to her.
The problem is that when the user writes the last line in the text box, the box scrolls down a bit, as you will see when you will run this code, so how can I disable the scrolling.
the code :
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Runtime.InteropServices;
namespace WindowsFormsApplication1
{
public partial class Form1 : Form
{
List<myRTB> pages; // collection of our RichTextBox, use as pages
public Form1()
{
InitializeComponent();
pages = new List<myRTB>();
pages.Add(new myRTB());
pages[0].Width = 200;
pages[0].Height = 290;
pages[0].Location = new Point(50, 10);
pages[0].Name = "0";
this.Controls.Add(pages[0]);
this.Width = 300;
this.Height = 360;
this.AutoScroll = true;
}
public void AddPage(int correntPageIndex)
{
if (correntPageIndex == (pages.Count - 1))
{
// create a new page
pages.Add(new myRTB());
pages[correntPageIndex + 1].Width = 200;
pages[correntPageIndex + 1].Height = 290;
pages[correntPageIndex + 1].Location = new Point(50, pages[correntPageIndex].Location.Y + 300);
this.Controls.Add(pages[pages.Count - 1]);
this.Name = (correntPageIndex + 1).ToString();
}
bool CursorInEnd = (pages[correntPageIndex].SelectionStart == pages[correntPageIndex].TextLength);
// Transfer the last word on the previous page, to the new page
int lastLineIndex = pages[correntPageIndex].GetLineFromCharIndex(pages[correntPageIndex].TextLength - 2);
// find the index of the first char in the last line
int indexOfFirstCharInLastLine = pages[correntPageIndex].GetFirstCharIndexFromLine(lastLineIndex);
// find the index of the last space in the last line
int indexOfLastSpace = pages[correntPageIndex].Text.LastIndexOf(' ', indexOfFirstCharInLastLine);
string restOfString;
if (indexOfLastSpace < 0) // no spaces in the last line
{
restOfString = pages[correntPageIndex].Text.Substring(pages[correntPageIndex].TextLength - 1);
pages[correntPageIndex + 1].Text.Insert(0, restOfString);
pages[correntPageIndex].Text.Remove(pages[correntPageIndex].TextLength - 1);
}
else // there is spaces in the last line
{
restOfString = pages[correntPageIndex].Text.Substring(indexOfLastSpace + 1);
pages[correntPageIndex + 1].Text = pages[correntPageIndex + 1].Text.Insert(0, restOfString);
pages[correntPageIndex].Text = pages[correntPageIndex].Text.Remove(indexOfLastSpace + 1);
}
if (CursorInEnd)
{
// Move the cursor to next page
pages[correntPageIndex + 1].SelectionStart = restOfString.Length;
pages[correntPageIndex + 1].Focus();
}
}
}
class myRTB : RichTextBox
{
public myRTB()
{
this.ScrollBars = RichTextBoxScrollBars.None;
}
protected override void WndProc(ref Message m)
{
// catch the request resize message
if (m.Msg == (WM_REFLECT | WM_NOTIFY))
{
REQRESIZE rrs = (REQRESIZE)(Marshal.PtrToStructure(m.LParam, typeof(REQRESIZE)));
if (rrs.nmhdr.code == EN_REQUESTRESIZE)
{
if (rrs.rc.ToRectangle().Height > this.ClientRectangle.Height)
{
((Form1)Parent).AddPage(int.Parse(this.Name));
}
}
}
base.WndProc(ref m);
}
[StructLayout(LayoutKind.Sequential)]
public struct NMHDR
{
public IntPtr HWND;
public uint idFrom;
public int code;
public override String ToString()
{
return String.Format("Hwnd: {0}, ControlID: {1}, Code: {2}",
HWND, idFrom, code);
}
}
[StructLayout(LayoutKind.Sequential)]
public struct REQRESIZE
{
public NMHDR nmhdr;
public RECT rc;
}
[StructLayout(LayoutKind.Sequential)]
public struct RECT
{
public int Left, Top, Right, Bottom;
public override string ToString()
{
return String.Format("{0}, {1}, {2}, {3}", Left, Top, Right,
Bottom);
}
public Rectangle ToRectangle()
{
return Rectangle.FromLTRB(Left, Top, Right, Bottom);
}
}
public const int WM_USER = 0x400;
public const int WM_NOTIFY = 0x4E;
public const int WM_REFLECT = WM_USER + 0x1C00;
public const int EN_REQUESTRESIZE = 0x701;
}
}

To ensure that the text does not scroll automatically, take a look at the following answer to a similar problem.
Disabling RichTextBox autoscroll
Here's another great answer to your problem:
Prevent Autoscrolling in RichTextBox
I copied over the code from the link above, please ensure to give that user credit for providing this code (its not mine)
[System.Runtime.InteropServices.DllImport("user32.dll")]
static extern IntPtr SendMessage(IntPtr hWnd, UInt32 Msg, Int32 wParam, Int32 lParam);
const int WM_USER = 0x400;
const int EM_HIDESELECTION = WM_USER + 63;
void OnAppend(string text)
{
bool focused = richTextBox1.Focused;
//backup initial selection
int selection = richTextBox1.SelectionStart;
int length = richTextBox1.SelectionLength;
//allow autoscroll if selection is at end of text
bool autoscroll = (selection==richTextBox1.Text.Length);
if (!autoscroll)
{
//shift focus from RichTextBox to some other control
if (focused)
textBox1.Focus();
//hide selection
SendMessage(richTextBox1.Handle, EM_HIDESELECTION, 1, 0);
}
richTextBox1.AppendText(text);
if (!autoscroll)
{
//restore initial selection
richTextBox1.SelectionStart = selection;
richTextBox1.SelectionLength = length;
//unhide selection
SendMessage(richTextBox1.Handle, EM_HIDESELECTION, 0, 0);
//restore focus to RichTextBox
if(focused) richTextBox1.Focus();
}
}