Does anyone know why the Listbox1.Refresh() command may not trigger the ListBox1_DrawItem sub every time?
In Microsoft Visual Basic 2010, a listbox has a forcolor and backcolor property. These properties change the forcolour and backcolor for all the items in the listbox. By default there is no property for the forecolor and backcolor of an individual item on a listbox, I am aware there is on a list view but I would still wish to use a listbox.
I am trying to have the ability to change the forecolor and backcolor properties of individual items in the listbox.
To do this the listbox's draw item sub must be used with the listbox's drawmode property set to OwnerDrawFixed. Then using a brush colour along with the e.graphics the forecolor or backcolor can be changed.
I have seen and followed examples of how to do this for the currently selected item. Such as the one from ehow's website.
What I am tiring to do however is change the colour of the litsbox item as it is added depending on a variable.
Here is my code:
Private Sub listbox_add()
Me.ListBox1.Items.Add(listbox_text(list_num)) ' adds the line to the list box
add_item_colour = True
ListBox1.Refresh()
End Sub
Private Sub ListBox1_DrawItem(ByVal sender As Object, ByVal e As System.Windows.Forms.DrawItemEventArgs) Handles ListBox1.DrawItem
Dim myBrush As Brush = Brushes.Black
e.DrawBackground()
If add_item_colour = True Then
If blue_message = True Then
myBrush = Brushes.Blue
Else
myBrush = Brushes.Black
End If
e.Graphics.DrawString(ListBox1.Items.Item(list_num), ListBox1.Font, myBrush, _
New RectangleF(e.Bounds.X, e.Bounds.Y, e.Bounds.Width, e.Bounds.Height))
add_item_colour = False
End If
e.DrawFocusRectangle()
End Sub
The listbox_text is a string array that stores the string being added, the list_num is a integer that increments when new items are added to the listbox and the blue_message is a Boolean that it true when I want a blue message and false when I don't.
The problem I seem to be having is that Listbox1.Refresh() command does not seem to be triggering the ListBox1_DrawItem sub every time it is called. I found this by using brake points. Does anyone know why this might be the case and how I could fix it?
Thanks, any help on this would be much appreciated.
First of all I suggest you to use background worker instead of directly writing down your code on UI thread.
Please refer the code below:
public partial class Form1 : Form
{
Brush myBrush = Brushes.Blue;
public Form1()
{
InitializeComponent();
this.backgroundWorker1.DoWork += backgroundWorker1_DoWork;
this.backgroundWorker1.RunWorkerCompleted += backgroundWorker1_RunWorkerCompleted;
this.backgroundWorker1.RunWorkerAsync(this);
}
private void listBox1_DrawItem(object sender, DrawItemEventArgs e)
{
e.DrawBackground();
e.Graphics.DrawString(listBox1.Items[e.Index].ToString(), listBox1.Font, myBrush, new RectangleF(e.Bounds.X, e.Bounds.Y, e.Bounds.Width, e.Bounds.Height));
e.DrawFocusRectangle();
}
private void button1_Click(object sender, EventArgs e)
{
this.backgroundWorker1.RunWorkerAsync(button1);
}
private void button2_Click(object sender, EventArgs e)
{
this.backgroundWorker1.RunWorkerAsync(button2);
}
void backgroundWorker1_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
this.listBox1.Refresh();
}
void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
{
if (e.Argument == this)
{
listBox1.Items.Add("p1");
listBox1.Items.Add("p2");
}
else if (e.Argument == this.button1)
{
myBrush = Brushes.Red;
listBox1.Refresh();
}
else if (e.Argument == this.button2)
{
myBrush = Brushes.Green;
if (listBox1.SelectedItem == null)
return;
var test = listBox1.Items[listBox1.SelectedIndex];
listBox1.SelectedItem = test;
var g = listBox1.CreateGraphics();
var rect = listBox1.GetItemRectangle(listBox1.SelectedIndex);
listBox1_DrawItem(listBox1, new DrawItemEventArgs(g, this.Font, rect, listBox1.SelectedIndex, DrawItemState.Default));
listBox1.Refresh();
}
}
}
Related
I'm making a Windows Forms application with VB.Net, Visual Studio 2015.
The Form has a WebBrowser control and other controls.
Whenever pressing the TAB key on keyboard, it always focuses on a html element loaded in the WebBrowser control first. Then pressing the TAB key again, the focus is switched between the HTML elements in the WebBrowser control.
Till ending up switching in all HTML elements, the focus doesn't switch to other controls in the Form.
Though I set .TabIndex = 1000 and .TabStop = false in the WebBrowser control, it always focuses on a html element loaded in the WebBrowser control first, always first.
So, I want to disable focusing on the WebBrowser control by pressing the TAB key or to disable the TAB key function in the Form entirely.
I have to get the answer done in VB.NET soon, but for now here's the C# version of it:
First, an extended web browser control, that you'll have to use on the form, with a custom event when the tab key is pressed.
Here we call the TabStop = false to ensure this key gets processed. Similar reasoning on WebBrowserShortcutsEnabled.
Then, we capture on the HTML Body, the key press event.
If the key code is a 9 (tab), we fire our event.
public class WebBrowserExtended : System.Windows.Forms.WebBrowser
{
protected virtual void OnTabKeyEvent(EventArgs e)
{
EventHandler handler = TabKeyEvent;
if (handler != null)
{
handler(this, e);
}
}
public event EventHandler TabKeyEvent;
public WebBrowserExtended() : base()
{
this.TabStop = false;
this.WebBrowserShortcutsEnabled = false;
}
protected override void OnDocumentCompleted(WebBrowserDocumentCompletedEventArgs e)
{
base.OnDocumentCompleted(e);
if (this.Document.Body != null)
this.Document.Body.KeyDown += new HtmlElementEventHandler(Body_KeyDown);
}
private void Body_KeyDown(Object sender, HtmlElementEventArgs e)
{
if (e.KeyPressedCode == 9 && !e.CtrlKeyPressed)
{
this.OnTabKeyEvent(e);
e.BubbleEvent = false;
}
}
}
And here's is your event handler:
private void webBrowser1_TabKeyEvent(object sender, EventArgs e)
{
var controls = new List<Control>(this.Controls.Cast<Control>());
var nextControl = controls.Where(c => c.TabIndex > webBrowser1.TabIndex).OrderBy(c => c.TabIndex).FirstOrDefault();
if (nextControl != null)
nextControl.Focus();
else
controls.OrderBy(c => c.TabIndex).FirstOrDefault().Focus();
}
And here's the VB version of the control:
Public Class WebBrowserExtended
Inherits System.Windows.Forms.WebBrowser
Protected Overridable Sub OnTabKeyEvent(ByVal e As EventArgs)
RaiseEvent TabKeyEvent(Me, e)
End Sub
Public Event TabKeyEvent As EventHandler
Public Sub New()
MyBase.New()
Me.TabStop = False
Me.WebBrowserShortcutsEnabled = False
End Sub
Protected Overrides Sub OnDocumentCompleted(ByVal e As WebBrowserDocumentCompletedEventArgs)
MyBase.OnDocumentCompleted(e)
If Me.Document.Body IsNot Nothing Then
AddHandler Me.Document.Body.KeyDown, AddressOf Body_KeyDown
End If
End Sub
Private Sub Body_KeyDown(ByVal sender As Object, ByVal e As HtmlElementEventArgs)
If e.KeyPressedCode = 9 AndAlso Not e.CtrlKeyPressed Then
Me.OnTabKeyEvent(e)
e.BubbleEvent = False
End If
End Sub
End Class
And the VB event handler:
Private Sub WebBrowser1_TabKeyEvent(sender As Object, e As EventArgs) Handles WebBrowser1.TabKeyEvent
Dim controls = New List(Of Control)(Me.Controls.Cast(Of Control))
Dim nextControl = controls.Where(Function(c)
Return c.TabIndex > WebBrowser1.TabIndex
End Function).OrderBy(Function(c)
Return c.TabIndex
End Function).FirstOrDefault()
If Not controls Is Nothing Then
nextControl.Focus()
Else
controls.OrderBy(Function(c)
Return c.TabIndex
End Function).FirstOrDefault().Focus()
End If
End Sub
enter code hereGiven this exmample:
Public Enum Gender
Masculine
Femenine
End Enum
public class ViewModel
private _gender as Gender
Public Property Gender() As Gender
Get
Return _gender
End Get
Set(ByVal value As Gender)
_gender = value
End Set
End Property
end class
Private Sub Form_Load
cmbGender.DataSource = [Enum].GetValues(GetType(Enums.Sexo)) //combobox shows gender ok
cmbGender.DataBindings.Add(New Binding("SelectedItem",ViewModel , "Gender", False, DataSourceUpdateMode.OnPropertyChanged))
end sub
Combobox use ViewModel getter to set its SelectedItem as soon as the Databindings.Add executes but never use the setter when SelectedItem change in the User Interface.
What I am doing wrong?
EDIT
Thanks to Sriram Sakthivel to enlighten me and check combobox events. The final situation is:
Using SelectedItem, DataSourceUpdateMode.OnValidation and combobox.causesValidation = true works when LostFocus raises. If you need onPropertyChanged you should use SelectedIndex and the Sriram Sakthivel's code below.
It will be updated in LostFocus event of ComboBox because SelectedItem doesn't raise change notification (which is necessary for immediate update).
As a workaround you can use SelectedIndex property, which publishes change notification via SelectedIndexChanged event. But there is a problem, SelectedIndex is of type Int32 you need to convert it to Gender and vice versa.
Here's how you'll do that: C# version
private void SetupBinding()
{
var binding = new Binding("SelectedIndex", model, "Gender", true, DataSourceUpdateMode.OnPropertyChanged);
binding.Format += binding_Format;
binding.Parse += binding_Parse;
comboBox1.DataBindings.Add(binding);
}
void binding_Parse(object sender, ConvertEventArgs e)
{
if (e.DesiredType == typeof(Gender))
{
e.Value = comboBox1.Items[(int)e.Value];
}
}
void binding_Format(object sender, ConvertEventArgs e)
{
if (e.DesiredType == typeof(int))
{
e.Value = comboBox1.Items.IndexOf(e.Value);
}
}
Am poor in Vb.net. So I used code converter to convert it to vb.net from c#.
Private Sub SetupBinding()
Dim binding = New Binding("SelectedIndex", model, "Gender", True, DataSourceUpdateMode.OnPropertyChanged)
AddHandler binding.Format, AddressOf binding_Format
AddHandler binding.Parse, AddressOf binding_Parse
comboBox1.DataBindings.Add(binding)
End Sub
Private Sub binding_Parse(sender As Object, e As ConvertEventArgs)
If e.DesiredType = GetType(Gender) Then
e.Value = comboBox1.Items(CInt(e.Value))
End If
End Sub
Private Sub binding_Format(sender As Object, e As ConvertEventArgs)
If e.DesiredType = GetType(Integer) Then
e.Value = comboBox1.Items.IndexOf(e.Value)
End If
End Sub
I've tried to disable the built-in right click menu of the shockwave flash element in my application, but it doesn't work. Is there a way to disable it in VB? Thanks!
it should disable the mouse right click event:
public partial class Form1 : Form ,IMessageFilter // after the name space
{
private const int WM_LBUTTONDOWN = 0x0201;
public Form1()
{
InitializeComponent();
Application.AddMessageFilter(this);
this.FormClosed += new FormClosedEventHandler(this.Form1_FormClosed);
}
private void Form1_FormClosed(object sender, FormClosedEventArgs e)
{
Application.RemoveMessageFilter(this);
}
public bool PreFilterMessage(ref Message m)
{
//Filter out WM_NCRBUTTONDOWN/UP/DBLCLK
if (m.Msg == 0xA4 || m.Msg == 0xA5 || m.Msg == 0xA6) return true;
// Filter out WM_RBUTTONDOWN/UP/DBLCLK
if (m.Msg == 0x204 || m.Msg == 0x205 || m.Msg == 0x206) return true;
return false;
}
This can give you a RightClick Disabled ShockWaveObject "only with 4 simple Steps"
On your "Form" Add a Shockwave Flash control.
1. Create a new Class file named "NoRightClickFlashControl.vb"
Paste the bellow code into NoRightClickFlashControl.vb
Public Class NoRightClickFlashControl
Inherits AxShockwaveFlashObjects.AxShockwaveFlash
Private Const WM_RBUTTONDOWN As Integer = &H204
Protected Overrides Sub WndProc(ByRef m As System.Windows.Forms.Message)
Select Case m.Msg
Case WM_RBUTTONDOWN
' Do nothing on right-click
m.Result = New IntPtr(1)
Return
End Select
MyBase.WndProc(m)
End Sub
End Class
2. Change the Name of your ShockwaveObject "AxShockwaveFlash1" to "NoRightClickFlashControl1" on your Form.
Open your Form.Designer.vb file
3. Change the code in between 'Initialize and SuspendLayout' like bellow :
Private Sub InitializeComponent()
'// Old is : Me.NoRightClickFlashControl1 = New AxShockwaveFlashObjects.AxShockwaveFlash()
'// Change like this
Me.NoRightClickFlashControl1 = New Your_Project_NameSpace.NoRightClickFlashControl
Me.SuspendLayout()
Then at Last, in Form.Designer.vb near the "End Class" file -- change the following :
'// Old is : Friend WithEvents NoRightClickFlashControl1 As AxShockwaveFlashObjects.AxShockwaveFlash
'// Change Like this :
Friend WithEvents NoRightClickFlashControl1 As NoRightClickFlashControl
End Class '// the End Class is just o understand.
All other coding is same to ShockwaveFlashObject - Load Movie, Play
It is Done
Press F5 to run! Enjoy!!!
How to presist XML Document on Post Back?
I have this xmlDocument to persist in SaveViewState() method:
Private _xmlSaveDispatch As XmlDocument = New XmlDocument
In my Page_Load...
If Not IsPostBack Then
Me._xmlSaveDispatch = New XmlDocument
Private Property XMLSaveDispatch As XmlDocument
Get
Return _xmlSaveDispatch
End Get
Set(value As XmlDocument)
_xmlSaveDispatch = value
End Set
End Property
Button Click Event:
Protected Sub dispatchButton_OnSave(sender As Object, e As EventArgs) _
Handles dispatchButtons.SaveDispatch
XMLSaveDispatch = _objDispatchInfo.GetSaveXML()
End Sub
I am writing a C# application and ran into the same issue (the asp:Xml tag does not persist between postbacks). Here is my code to persist it in C#:
//.aspx Presentation
<asp:Xml ID="xmlFormDisplay" runat="server"></asp:Xml>
//.aspx.cs Code Behind
private string formXSLT
{
get { return ViewState["FormXSLT"].ToString(); }
set { ViewState["FormXSLT"] = value; }
}
private string formXML
{
get { return ViewState["FormXML"].ToString(); }
set { ViewState["FormXML"] = value; }
}
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
...
}
xmlFormDisplay.TransformSource = formXSLT;
xmlFormDisplay.DocumentContent = formXML;
}
I'm not much of a VB developer, but this ought to work (or be pretty close):
//.aspx Presentation
<asp:Xml ID="xmlFormDisplay" runat="server"></asp:Xml>
//.aspx.vb Code Behind
Private Property FormXSLT As String
Get
Return ViewState["FormXSLT"].ToString()
End Get
Set(value As String)
ViewState["FormXSLT"] = value
End Set
End Property
Private Property FormXML As String
Get
Return ViewState["FormXML"].ToString()
End Get
Set(value As String)
ViewState["FormXML"] = value
End Set
End Property
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
If Not IsPostBack Then
...
End If
xmlFormDisplay.TransformSource = formXSLT
xmlFormDisplay.DocumentContent = formXML
End Sub
Can I change my button control to toggle-button?
Is there any simple way to change the button property to make it toggle button?
According to this post on OSIX all you need to do is use a CheckBox but set it's appearance to Button.
In code:
CheckBox checkBox1 = new System.Windows.Forms.CheckBox();
checkBox1.Appearance = System.Windows.Forms.Appearance.Button;
(C# code but you see how it works).
But you can do this from the Properties dialog in the designer.
To Change Checkbox to Simple Latching On/Off Button
myCheckBox.Appearance = System.Windows.Forms.Appearance.Button
To Add Custom Toggle (Sliding) On/Off Switch
Right click project in VS and select 'Add' then 'User Control...'
Name your new file "Toggle.vb"
Paste the code below
Switch to your form and drag your 'toggle' control from toolbox to form
Size & settings can be changed like standard control
Colors can be changed in OnPaint method of Toggle Class
VB.net
Imports System.Drawing
Imports System.Drawing.Drawing2D
Imports System.Windows.Forms
Public Class Toggle
Inherits System.Windows.Forms.UserControl
Private _checked As Boolean
Public Property Checked As Boolean
Get
Return _checked
End Get
Set(ByVal value As Boolean)
If Not _checked.Equals(value) Then
_checked = value
Me.OnCheckedChanged()
End If
End Set
End Property
Protected Overridable Sub OnCheckedChanged()
RaiseEvent CheckedChanged(Me, EventArgs.Empty)
End Sub
Public Event CheckedChanged(ByVal sender As Object, ByVal e As EventArgs)
Protected Overrides Sub OnMouseClick(e As MouseEventArgs)
Me.Checked = Not Me.Checked
Me.Invalidate()
MyBase.OnMouseClick(e)
End Sub
Protected Overrides Sub OnPaint(ByVal e As PaintEventArgs)
Me.OnPaintBackground(e)
e.Graphics.SmoothingMode = SmoothingMode.AntiAlias
Using path = New GraphicsPath()
Dim d = Padding.All
Dim r = Me.Height - 2 * d
path.AddArc(d, d, r, r, 90, 180)
path.AddArc(Me.Width - r - d, d, r, r, -90, 180)
path.CloseFigure()
e.Graphics.FillPath(If(Checked, Brushes.DarkGray, Brushes.LightGray), path)
r = Height - 1
Dim rect = If(Checked, New System.Drawing.Rectangle(Width - r - 1, 0, r, r), New System.Drawing.Rectangle(0, 0, r, r))
e.Graphics.FillEllipse(If(Checked, Brushes.Green, Brushes.LightSlateGray), rect)
End Using
End Sub
End Class
C#
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Windows.Forms;
namespace Your_Project_Name
{
class Toggle : CheckBox
{
public Toggle()
{
SetStyle(ControlStyles.UserPaint | ControlStyles.AllPaintingInWmPaint, true);
Padding = new Padding(6);
}
protected override void OnPaint(PaintEventArgs e)
{
this.OnPaintBackground(e);
e.Graphics.SmoothingMode = SmoothingMode.AntiAlias;
using (var path = new GraphicsPath())
{
var d = Padding.All;
var r = this.Height - 2 * d;
path.AddArc(d, d, r, r, 90, 180);
path.AddArc(this.Width - r - d, d, r, r, -90, 180);
path.CloseFigure();
e.Graphics.FillPath(Checked ? Brushes.DarkGray : Brushes.LightGray, path);
r = Height - 1;
var rect = Checked ? new System.Drawing.Rectangle(Width - r - 1, 0, r, r)
: new System.Drawing.Rectangle(0, 0, r, r);
e.Graphics.FillEllipse(Checked ? Brushes.Green : Brushes.LightSlateGray, rect);
}
}
}
}
This code is from several sources over the years and has some minor tweaks. It appears it exist in various forms on different sites so it's unclear who to attribute
All code was tested in Visual Studio 2017
If i understood correctly, you can achieve this functionality by using a flag. For example:
bool isClicked = false;
and in the clicked event to put the following code to invert the bool:
isClicked = !isClicked;