We Keep Coding

DateTimePicker control in ContextMenuStrip

I have added a DateTimePicker in ContextMenuStrip using ToolStripControlHost. I am using below code.
DateTimePicker startDate = new DateTimePicker();
(cms.Items["mnuStartDate"] as ToolStripMenuItem).DropDownItems.Add(new ToolStripControlHost(startDate));
Selecting of date is working but when I clicked on the arrows to go to the previous or next month, or if I clicked on the Month, the ToolStrip is closing. Is there any workaround here? Thanks.
Note: I am showing the cms(ContextMenuStrip ) when Right Clicking on a control.

Looks like the ToolStrip behavior closes when an item is selected. So I juts used CalendarMonth Control as a replacement. Link here

It seems to be related to Application.EnableVisualStyles(); When not-enabled, the menu doesn't unexpectedly close.
When enabled, to prevent closing, detect if the CalendarMonth menu is currently visible, and if the mouse was clicked on it.
public class DatePicker : DateTimePicker {
private const int DtmFirst = 0x1000;
private const int DtmGetmonthcal = (DtmFirst + 8);
private bool isDroppedDown = false;
private IntPtr hwndCalendarWindow = IntPtr.Zero;
protected override void OnDropDown(EventArgs e) {
isDroppedDown = true;
hwndCalendarWindow = SendMessage(Handle, DtmGetmonthcal, 0, 0);
base.OnDropDown(e);
}
protected override void OnCloseUp(EventArgs eventargs) {
isDroppedDown = false;
base.OnCloseUp(eventargs);
}
public bool CalendarMonthClicked(Point pt) {
if (!isDroppedDown)
return false;
RECT r = new RECT();
GetWindowRect(hwndCalendarWindow, out r);
return pt.X >= r.Left && pt.X <= r.Right && pt.Y >= r.Top && pt.Y <= r.Bottom;
}
[DllImport("user32.dll")]
private static extern bool GetWindowRect(IntPtr hWnd, out RECT lpRect);
[DllImport("User32.dll")]
private static extern IntPtr SendMessage(IntPtr h, int msg, int param, int data);
[StructLayout(LayoutKind.Sequential)]
private struct RECT {
public int Left, Top, Right, Bottom;
}
}
static class Program {
//[DllImport("uxtheme.dll", ExactSpelling = true, CharSet = CharSet.Unicode)]
//public extern static Int32 SetWindowTheme(IntPtr hWnd, String textSubAppName, String textSubIdList);
[STAThread]
static void Main() {
Application.EnableVisualStyles(); // if you disable visual styles then the menu won't close
DatePicker dpStart = new DatePicker();
dpStart.MinimumSize = new Size(100, 50);
Form ff = new Form();
ContextMenuStrip cms = new ContextMenuStrip();
ToolStripMenuItem menu = new ToolStripMenuItem("Menu");
menu.DropDown.Closing += (o, e) => {
e.Cancel = (e.CloseReason == ToolStripDropDownCloseReason.AppClicked && dpStart.CalendarMonthClicked(Cursor.Position));
};
// sub-menu doesn't close properly, probably related to the ToolStripControlHost
cms.Opening += delegate {
menu.DropDown.Close(ToolStripDropDownCloseReason.CloseCalled);
};
cms.Closed += delegate {
menu.DropDown.Close(ToolStripDropDownCloseReason.CloseCalled);
};
ff.ContextMenuStrip = cms;
cms.Items.Add(menu);
ToolStripControlHost item = new ToolStripControlHost(dpStart) { AutoSize = true };
menu.DropDownItems.Add(item);
Application.Run(ff);
}
}

Scrollbar resetting to the top of the treeView after sorting?

I have a fairly large tree structure, and whenever a user adds or removes a child node, the tree is re-sorted. This all works very well, but my issue is this: After the sorting, the scrollbar is automatically reset to the top of the tree. I'd like to make it so the scrollbar holds (or returns to) the position where the node was just added or deleted so the user doesn't have to scroll down and find the parent node every single time they want to add or delete something.
I've been trying to find some way to do this for some time now, but haven't had any luck. Does anyone have any tips?
Here's the method I'm using for removing a child node, if it helps:
private void RemoveFromCategoryEvent(object sender, EventArgs e)
{
SuspendLayout();
if (treeViewCategories.SelectedNode != null)
{
TreeNode treeNode = treeViewCategories.SelectedNode;
TreeNode parentNode = treeNode.Parent;
if ((settingGroup != null) && (settingGroup.GroupRootCategory != null)
&& (settingGroup.GroupRootCategory.Settings != null) && (treeNode.Tag is ISetting)
&& (parentNode.Tag is IDeviceSettingCategory))
{
ISetting currentSetting = treeNode.Tag as ISetting;
(parentNode.Tag as IDeviceSettingCategory).Settings.Remove(currentSetting);
treeNode.Remove();
settingGroup.GroupRootCategory.Settings.Add(currentSetting);
TreeNode settingNode = rootCategoryNode.Nodes.Add(currentSetting.ShortName);
settingNode.Tag = currentSetting;
settingNode.ImageIndex = Utilities.SettingCategoryChildImage;
settingNode.SelectedImageIndex = Utilities.SettingCategoryChildImage;
treeViewCategories.Sort(); //scrollbar reset happens here
}
}
ResumeLayout();
}

You can use P/Invoke to get the current scroll position, save it, and then restore it after sorting.
You will need the following API Calls:
[DllImport("user32.dll", CharSet = System.Runtime.InteropServices.CharSet.Auto)]
public static extern int GetScrollPos(int hWnd, int nBar);
[DllImport("user32.dll")]
static extern int SetScrollPos(IntPtr hWnd, int nBar, int nPos, bool bRedraw);
private const int SB_HORZ = 0x0;
private const int SB_VERT = 0x1;
Getting the current position:
private Point GetTreeViewScrollPos(TreeView treeView)
{
return new Point(
GetScrollPos((int)treeView.Handle, SB_HORZ),
GetScrollPos((int)treeView.Handle, SB_VERT));
}
Setting the position:
private void SetTreeViewScrollPos(TreeView treeView, Point scrollPosition)
{
SetScrollPos((IntPtr)treeView.Handle, SB_HORZ, scrollPosition.X, true);
SetScrollPos((IntPtr)treeView.Handle, SB_VERT, scrollPosition.Y, true);
}

How to prevent TextBox auto scrolls when append text?

I have a multi-line TextBox with a vertical scrollbar that logs data from real-time processing. Currently, whenever a new line is added by textBox.AppendText(), the TextBox scrolls to the bottom so you can see the last entry, this great. But I have a checkbox to indicate whether TextBox is allowed to auto-scroll. Is there any way to do this?
Note:
I want to use the TextBox because the added text has multi-lines and alignment by whitespace, so it's not simple to use with a ListBox or a ListView.
I tried to add a new line by textBox.Text += text, but the TextBox constantly scrolls to the top.
If we have a solution to do that, then one more question is how to prevent the TextBox auto scrolls when the user uses the scrollbar to view somewhere else in the TextBox while the TextBox appends text?
private void OnTextLog(string text)
{
if (chkAutoScroll.Checked)
{
// This always auto scrolls to the bottom.
txtLog.AppendText(Environment.NewLine);
txtLog.AppendText(text);
// This always auto scrolls to the top.
//txtLog.Text += Environment.NewLine + text;
}
else
{
// I want to append the text without scrolls right here.
}
}
Update 1: As saggio suggests, I also think the solution to this problem is to determine the position of the first character in the current text that is displayed in the TextBox before appending text and restoring it after that. But how to do this? I tried to record the current cursor position like this, but it did not help:
int selpoint = txtLog.SelectionStart;
txtLog.AppendText(Environment.NewLine);
txtLog.AppendText(text);
txtLog.SelectionStart = selpoint;
Update 2 (the issue was resolved): I found a solution that can solve my issue here on Stack Overflow. I have optimized their code to suit my case as follows:
// Constants for extern calls to various scrollbar functions
private const int SB_VERT = 0x1;
private const int WM_VSCROLL = 0x115;
private const int SB_THUMBPOSITION = 0x4;
[DllImport("user32.dll", CharSet = CharSet.Auto)]
private static extern int GetScrollPos(IntPtr hWnd, int nBar);
[DllImport("user32.dll")]
private static extern int SetScrollPos(IntPtr hWnd, int nBar, int nPos, bool bRedraw);
[DllImport("user32.dll")]
private static extern bool PostMessageA(IntPtr hWnd, int nBar, int wParam, int lParam);
[DllImport("user32.dll")]
private static extern bool GetScrollRange(IntPtr hWnd, int nBar, out int lpMinPos, out int lpMaxPos);
private void AppendTextToTextBox(TextBox textbox, string text, bool autoscroll)
{
int savedVpos = GetScrollPos(textbox.Handle, SB_VERT);
textbox.AppendText(text + Environment.NewLine);
if (autoscroll)
{
int VSmin, VSmax;
GetScrollRange(textbox.Handle, SB_VERT, out VSmin, out VSmax);
int sbOffset = (int)((textbox.ClientSize.Height - SystemInformation.HorizontalScrollBarHeight) / (textbox.Font.Height));
savedVpos = VSmax - sbOffset;
}
SetScrollPos(textbox.Handle, SB_VERT, savedVpos, true);
PostMessageA(textbox.Handle, WM_VSCROLL, SB_THUMBPOSITION + 0x10000 * savedVpos, 0);
}
private void OnTextLog(string text)
{
AppendTextToTextBox(txtLog.Text, Environment.NewLine + text, chkAutoScroll.Checked);
}
Another way:
private const int SB_VERT = 0x1;
private const int WM_VSCROLL = 0x115;
private const int SB_THUMBPOSITION = 0x4;
private const int SB_BOTTOM = 0x7;
[DllImport("user32.dll", CharSet = CharSet.Auto)]
private static extern int GetScrollPos(IntPtr hWnd, int nBar);
[DllImport("user32.dll")]
private static extern int SetScrollPos(IntPtr hWnd, int nBar, int nPos, bool bRedraw);
[DllImport("user32.dll")]
private static extern bool PostMessageA(IntPtr hWnd, int nBar, int wParam, int lParam);
private void AppendTextToTextBox(TextBox textbox, string text, bool autoscroll)
{
int savedVpos = GetScrollPos(textbox.Handle, SB_VERT);
textbox.AppendText(text + Environment.NewLine);
if (autoscroll)
{
PostMessageA(textbox.Handle, WM_VSCROLL, SB_BOTTOM, 0);
}
else
{
SetScrollPos(textbox.Handle, SB_VERT, savedVpos, true);
PostMessageA(textbox.Handle, WM_VSCROLL, SB_THUMBPOSITION + 0x10000 * savedVpos, 0);
}
}
I post these solutions for those who have a similar issue. Thanks for cgyDeveloper's source code.
Does anyone have a more straightforward way?

This seems pretty straight forward but I may be missing something. Use append text to scroll to the position if Autochecked is true and just add the text if you do not wish to scroll.
Update...I was missing something. You want to set the selection point and then scroll to the caret. See below.
if (chkAutoScroll.Checked)
{
// This always auto scrolls to the bottom.
txtLog.AppendText(Environment.NewLine);
txtLog.AppendText(text);
// This always auto scrolls to the top.
//txtLog.Text += Environment.NewLine + text;
}
else
{
int caretPos = txtLog.Text.Length;
txtLog.Text += Environment.NewLine + text;
txtLog.Select(caretPos, 0);
txtLog.ScrollToLine(txtLog.GetLineIndexFromCharacterIndex(caretPos));
}

You have to do it something like this,
textBox1.AppendText("Your text here");
// this selects the index zero as the location of your caret
textBox1.Select(0, 0);
// Scrolls to the caret :)
textBox1.ScrollToCaret();
Tested and working on VS2010 c# Winforms, i dont know about WPF but google probably has the answer for you.

The desired actions are:
To turn on autoscrolling when the scrollbar is dragged to the bottom.
To turn off autoscrolling when the scollbar is dragged anywhere else.
create the following class
public class AutoScrollTextBox : TextBox
{
protected override void OnInitialized(EventArgs e)
{
base.OnInitialized(e);
VerticalScrollBarVisibility = ScrollBarVisibility.Auto;
HorizontalScrollBarVisibility = ScrollBarVisibility.Disabled;
}
protected override void OnTextChanged(TextChangedEventArgs e)
{
bool isScrolledToEnd = VerticalOffset + ViewportHeight == ExtentHeight;
base.OnTextChanged(e);
CaretIndex = Text.Length;
if (isScrolledToEnd)
{
ScrollToEnd();
}
}
}
And replace the TextBox with AutoScrollTextBox in your XML and append to the TextToDisplay binding as stuff arrives for display
<local:AutoScrollTextBox Text="{Binding TextToDisplay }" />

How to Disable Autoscrolling in richtextbox in c#

i want to disable the scrolling feature of richtextbox in c#. i just want to make richtextbox to allow user to enter only in its size area, means no vertical scrolling for user. just like MS-word or open Office Pages.thanx in advance.

You should override WndProc and block WM_SETFOCUS.
protected override void WndProc(ref Message m)
{
if(m.Msg != WM_SETFOCUS)
base.WndProc(ref m);
}
Here is a tutorial about this : How to: C# - Prevent RichTextBox from auto scrolling

This worked for me.
First thing as you may have seen in other posts you need access to user32.dll from C#.
[System.Runtime.InteropServices.DllImport("user32.dll")]
public static extern IntPtr SendMessage(IntPtr hWnd, UInt32 Msg, Int32 wParam, Int32 lParam);
[System.Runtime.InteropServices.DllImport("user32.dll")]
private static extern int SendMessage(IntPtr hwndLock,Int32 wMsg,Int32 wParam, ref Point pt);
We need to make some constant declaration to make the SendMessage calls properly.
private const int WM_USER = 0x400;
private const int EM_HIDESELECTION = WM_USER + 63;
private const int WM_SETREDRAW = 0x000B;
private const int EM_GETSCROLLPOS = WM_USER + 221;
private const int EM_SETSCROLLPOS = WM_USER + 222;
Then, some public static methods to be used whenever we need to stop scrolling.
public static void Suspend(Control control)
{
Message msgSuspendUpdate = Message.Create(control.Handle, WM_SETREDRAW, IntPtr.Zero,
IntPtr.Zero);
NativeWindow window = NativeWindow.FromHandle(control.Handle);
window.DefWndProc(ref msgSuspendUpdate);
}
public static void Resume(Control control)
{
// Create a C "true" boolean as an IntPtr
IntPtr wparam = new IntPtr(1);
Message msgResumeUpdate = Message.Create(control.Handle, WM_SETREDRAW, wparam,
IntPtr.Zero);
NativeWindow window = NativeWindow.FromHandle(control.Handle);
window.DefWndProc(ref msgResumeUpdate);
control.Invalidate();
}
public static Point GetScrollPoint(Control control) {
Point point = new Point();
SendMessage(control.Handle, EM_GETSCROLLPOS, 0, ref point);
return point;
}
public static void SetScrollPoint(Control control, Point point)
{
SendMessage(control.Handle, EM_SETSCROLLPOS, 0, ref point);
}
The Suspend method stops the Control to make a redraw on the screen. The Resume method restarts redraws on the screen for the given Control.
The GetScrollPoint method gets the actual Point where the scroll caret is located. The SetScrollPoint puts the scroll caret at the given point.
How to use these methods? First, given a Control you need to stop autoscroll, make the call to Suspend, then to GetScrollPoint, (make what you need to do with the control, like highlight or append text) then SetScrollPoint and finally Resume.
In my case, I wanted to copy the entire line of a RichTextBox at any time when the cursor moves from line to line. (Doing so produce a scroll on long lines).
This is my working method:
private int intLastLine = -1;
private void richTextBoxSwitch_SelectionChanged(object sender, EventArgs e)
{
try
{
if (this.richTextBoxSwitch.TextLength > 0)
{
ControlBehavior.Suspend(this.richTextBoxSwitch);
Point point = ControlBehavior.GetScrollPoint(this.richTextBoxSwitch);
int intSelectionStartBackup = this.richTextBoxSwitch.SelectionStart;
int intSelectionLengthBackup = this.richTextBoxSwitch.SelectionLength;
int intCharIndex = this.richTextBoxSwitch.GetFirstCharIndexOfCurrentLine();
int intLine = this.richTextBoxSwitch.GetLineFromCharIndex(intCharIndex);
this.richTextBoxSwitch.SuspendLayout();
if (intLastLine != intLine)
{
intLastLine = intLine;
int intLength = this.richTextBoxSwitch.Lines[intLine].Length;
this.richTextBoxSwitch.Select(intCharIndex, intLength);
this.richTextBoxSwitch.BackColor = ColorMessageBackground;
strData = this.richTextBoxSwitch.SelectedText;
this.textBoxMessageSelected.Text = strData.Trim();
this.richTextBoxSwitch.Select(intSelectionStartBackup, intSelectionLengthBackup);
}
this.richTextBoxSwitch.ResumeLayout();
ControlBehavior.SetScrollPoint(this.richTextBoxSwitch, point);
ControlBehavior.Resume(this.richTextBoxSwitch);
}
}
catch (Exception ex)
{
MessageBox.Show(ex.ToString());
}
}
Hope this helps!

mouse wheel scroll horizontally

I have a panel whose AutoScroll = true;
I can scroll the panel using scrollbars.
I also find mousewheel "vertical scroll" with "mouse" wheel by writing:
void panelInner_MouseWheel(object sender, System.Windows.Forms.MouseEventArgs e)
{
panelInner.Focus();
}
However, I want to scroll horizontally by "wheeling mouse + shift" too.
What do I need to do for that to happen?

In your designer file, you'll need to manually add a MouseWheel event delegate.
this.panelInner.MouseWheel += new System.Windows.Forms.MouseEventHandler(this.panelInner_MouseWheel);
Then, in your code behind, you can add the following.
private const int WM_SCROLL = 276; // Horizontal scroll
private const int SB_LINELEFT = 0; // Scrolls one cell left
private const int SB_LINERIGHT = 1; // Scrolls one line right
[DllImport("user32.dll", CharSet = CharSet.Auto)]
private static extern int SendMessage(IntPtr hWnd, int wMsg, IntPtr wParam, IntPtr lParam);
private void panelInner_MouseWheel(object sender, MouseEventArgs e)
{
if (ModifierKeys == Keys.Shift)
{
var direction = e.Delta > 0 ? SB_LINELEFT : SB_LINERIGHT;
SendMessage(this.panelInner.Handle, WM_SCROLL, (IntPtr)direction, IntPtr.Zero);
}
}
References:
Shift + mouse wheel horizontal scrolling
Mouse tilt wheel horizontal scrolling in C#