Develop Reference

Zooming in ComboBox not working as expected

I have an application that scans an image to display on the application. After the image is scanned, I have the option to zoom the image. There's a combo box on the application that display the zoom percentage as well.
I can zoom fine using my mouse wheel and the combo box % changes accordingly which is fine. The problem happens if I manually select the combo box and select a zoom percentage, say 50%, then there's no changes at all.
Code:
private void ImageBox_ZoomLevelsChanged(object sender, EventArgs e)
{
this.FillZoomLevels();
}
private void ZoomComboBox_Click(object sender, EventArgs e)
{
}
private void FillZoomLevels()
{
ZoomComboBox.Items.Clear();
foreach (int zoom in ImageBox.ZoomLevels)
ZoomComboBox.Items.Add(string.Format("{0}%", zoom));
}
Am I doing anything wrong? Appreciate any help.

When there is more than one control on the Panel, and the ScrollBars are shown, the MouseWheel event of the Panel would be raised, but if there's only a PictureBox on the Panel whose Image large enough to make the panel's ScrollBars visible, then the MouseWheel event of the Panel won't be raised, instead, the Form's MouseWheel event fires.
In the following sample, I just add a PictureBox onto the Panel without any other controls added, set a large Image to the PictureBox which make the Panel's ScrollBars invisible, since there's only one control on the panel, the MouseWheel event of the Panel won't be raised, but the Form's MouseWheel event be raised, we handle this event instead, handle the Form's KeyDown and KeyUp events as well.
Furthermore, set the SizeMode of the PictureBox to StretchImage instead of AutoSize, thus when we change the size of the PictureBox, the Image in the PictureBox will resize to fit the PictureBox.
The PictureBox.Scale() method won't help you in this screnario, change the size of the PictureBox instead.
public partial class Form4 : Form
{
public Form4()
{
InitializeComponent();
}
bool ctrlKeyDown;
bool shiftKeyDown;
private void Form4_Load(object sender, EventArgs e)
{
this.ctrlKeyDown = false;
this.shiftKeyDown = false;
//If there's only PictureBox control on the panel, the MouseWheel event of the form raised
//instead of the MouseWheel event of the Panel.
this.MouseWheel += new MouseEventHandler(Form4_MouseWheel);
this.KeyDown += new KeyEventHandler(Form4_KeyDown);
this.KeyUp += new KeyEventHandler(Form4_KeyUp);
//this is important for zooming the image
this.pictureBox2.SizeMode = PictureBoxSizeMode.StretchImage;
}
void Form4_KeyUp(object sender, KeyEventArgs e)
{
this.ctrlKeyDown = e.Control;
this.shiftKeyDown = e.Shift;
}
void Form4_KeyDown(object sender, KeyEventArgs e)
{
this.ctrlKeyDown = e.Control;
this.shiftKeyDown = e.Shift;
}
void Form4_MouseWheel(object sender, MouseEventArgs e)
{
bool IsGoUp = e.Delta > 0 ? true : false;
if (this.ctrlKeyDown)
{
if (IsGoUp && this.panel1.HorizontalScroll.Value > 5)
{
this.panel1.HorizontalScroll.Value -= 5;
}
if (!IsGoUp && this.panel1.HorizontalScroll.Value < this.panel1.HorizontalScroll.Maximum - 5)
{
this.panel1.HorizontalScroll.Value += 5;
}
}
else if (this.shiftKeyDown)
{
int hStep = (int)(this.pictureBox2.Image.Width * 0.02);
int vStep = (int)(this.pictureBox2.Image.Height * 0.02);
if (IsGoUp)
{
this.pictureBox2.Width += hStep;
this.pictureBox2.Height += vStep;
}
else
{
this.pictureBox2.Width -= hStep;
this.pictureBox2.Height -= vStep;
}
}
else
{
if (IsGoUp && this.panel1.VerticalScroll.Value > 5)
{
this.panel1.VerticalScroll.Value -= 5;
}
if (!IsGoUp && this.panel1.VerticalScroll.Value < this.panel1.VerticalScroll.Maximum - 5)
{
this.panel1.VerticalScroll.Value += 5;
}
}
}
}

How to make sidebar?

I am using C# programming language.
I have created a new borderless Windows Form in Visual Studio 2012. I have two panels. First panel (panel1) is docked at top and second panel (panel2) is docked at left and its Visible status is false. I also added a button (buttonMenu) in panel1 and docked it on left. What I am trying to achieve is that on buttonMenu click, panel2 slides from left to its original location (left dock) and when buttonMenu clicked again slides away.
I have tried to set the following code:
private void buttonMenu_Click(object sender, EventArgs e)
{
panel2.Visible = !panel2.Visible;
}
And it works but i am trying to make it slide with an animation.

The easier way to do it would be to create a timer and in its Tick event change the panel width like so
private Timer timer = new Timer();
bool closing = false;
int desiredWidth = 300
private void ConfigureTimer()
{
timer.Tick += timer_Tick;
timer.Interval = 16;
}
private void timer_Tick(object sender, EventArgs e){
{
if(closing)
{
panel2.Width-=15;
if(panel2.Width < 0)
{
panel2.Width = 0;
timer.Stop();
}
}else{
panel2.Width+=15;
if(panel2.Width >= desiredWidth)
{
panel2.Width = desiredWidth;
timer.Stop();
}
}
}
private void SwitchPanelState()
{
closing = !closing;
timer.Start();
}
But if you want to make you life easy and more object oriented, you should create an Control with the specified behavior and just add it in your form

How mouse enter event work on disabled panel to display it?

I have panel on main form in disabled state I want to enable it by mouse enter event. How can I?
private void pnlOne_MouseEnter(object sender, EventArgs e)
{
pnlOne.Enabled = true;
pnlOne.Visible = true;
}
I try above one but it not working...

If you have Disabled your control mouse event wont get fired. You cant do this.
Even if you enabled some other events,Check whether your panel is in the front . Use bring to front in the designer. Reason could be another container control is in the middle.

You can try a MouseMove event on Panel's parent control. In that you can check cursor position and if cursor is on Panel, you can enable Panel.
private void PANELS_PARENT_CONTROL_MouseMove(object sender, MouseEventArgs e)
{
if (e.Location.X > pnlOne.Location.X &&
e.Location.X < (pnlOne.Location.X + pnlOne.Width) &&
e.Location.Y > pnlOne.Location.Y &&
e.Location.Y < (pnlOne.Location.Y + pnlOne.Height))
{
pnlOne.Enabled = true;
pnlOne.Visible = true;
}
else
{
pnlOne.Enabled = false;
pnlOne.Visible = false;
}
}

Move Item from one cell to another

I have a tableLayoutPanel with 16 cells. 15 of the cells have controls. I want to be able to move the controls from one cell to another at runtime.
I have used
private void button15_Click(object sender, EventArgs e)
{
tableLayoutPanel1.Controls.Remove(button15);
tableLayoutPanel1.Controls.Add(button15, 3, 3);
}
This works well but i want to know if there is any better way to do this???

In Winforms, you can only move a control inside its parent (of course there are some exceptions to some controls which in fact don't have any Parent). So the idea here is if you want to move a control of your TableLayoutPanel, you have to set its Parent to your Form of another container when mouse is held down, when moving, the position of the control is in the new parent, after mouse is released, we have to set the Parent of the control to the TableLayoutPanel back, of course we have to find the drop-down cell position and use SetCellPosition method to position the control on the TableLayoutPanel, here is the demo code for you (works great), I use 2 Buttons in this demo, you can replace them with any control you want:
public partial class Form1 : Form {
public Form1() {
InitializeComponent();
//This will prevent flicker
typeof(TableLayoutPanel).GetProperty("DoubleBuffered", System.Reflection.BindingFlags.NonPublic | System.Reflection.BindingFlags.Instance).SetValue(tableLayoutPanel1, true, null);
}
Point downPoint;
bool moved;
//This is used to store the CellBounds together with the Cell position
//so that we can find the Cell position later (after releasing mouse).
Dictionary<TableLayoutPanelCellPosition, Rectangle> dict = new Dictionary<TableLayoutPanelCellPosition, Rectangle>();
//MouseDown event handler for all your controls (on the tableLayoutPanel1)
private void Buttons_MouseDown(object sender, MouseEventArgs e) {
Control button = sender as Control;
button.Parent = this;
button.BringToFront();
downPoint = e.Location;
}
//MouseMove event handler for all your controls (on the tableLayoutPanel1)
private void Buttons_MouseMove(object sender, MouseEventArgs e) {
Control button = sender as Control;
if (e.Button == MouseButtons.Left) {
button.Left += e.X - downPoint.X;
button.Top += e.Y - downPoint.Y;
moved = true;
tableLayoutPanel1.Invalidate();
}
}
//MouseUp event handler for all your controls (on the tableLayoutPanel1)
private void Buttons_MouseUp(object sender, MouseEventArgs e) {
Control button = sender as Control;
if (moved) {
SetControl(button, e.Location);
button.Parent = tableLayoutPanel1;
moved = false;
}
}
//This is used to set the control on the tableLayoutPanel after releasing mouse
private void SetControl(Control c, Point position) {
Point localPoint = tableLayoutPanel1.PointToClient(c.PointToScreen(position));
var keyValue = dict.FirstOrDefault(e => e.Value.Contains(localPoint));
if (!keyValue.Equals(default(KeyValuePair<TableLayoutPanelCellPosition, Rectangle>))) {
tableLayoutPanel1.SetCellPosition(c, keyValue.Key);
}
}
//CellPaint event handler for your tableLayoutPanel1
private void tableLayoutPanel1_CellPaint(object sender, TableLayoutCellPaintEventArgs e) {
dict[new TableLayoutPanelCellPosition(e.Column, e.Row)] = e.CellBounds;
if (moved) {
if (e.CellBounds.Contains(tableLayoutPanel1.PointToClient(MousePosition))) {
e.Graphics.FillRectangle(Brushes.Yellow, e.CellBounds);
}
}
}
}

Remove Lock & set dock to none and move!

Mouse Cursor position changes

Hi I have a windows form application which i want to move my mouse then dragdrop will function but i have tried using mousemove mouse event to do it , but seems like dragdrop is very sensitive.So what i'm asking is whether is it possible to detect if the mouse cursor moves at least a certain distance away from the current cursor then it does the dragdrop code.

I understand you have a drag & drop code you want to execute only if the mouse has moved a certain distance. If so:
You can hook to the mouse move event once the user has performed the initial action (mouse down on the item to drag ?). Then compare the mouse coordinates on the mouse move event and trigger the "dragdrop code" once the coordinates difference is higher then the arbitrary value you set.
private int difference = 10;
private int xPosition;
private int yPosition;
private void item_MouseDown(object sender, MouseEventArgs e)
{
this.MouseMove += new MouseEventHandler(Form_MouseMove);
xPosition = e.X;
yPosition = e.Y;
}
private void Form_MouseMove(object sender, MouseEventArgs e)
{
if (e.X < xPosition - difference
|| e.X > xPosition + difference
|| e.Y < yPosition - difference
|| e.Y > yPosition + difference)
{
//Execute "dragdrop" code
this.MouseMove -= Form_MouseMove;
}
}
This would execute dragdrop when the cursor moves out of a virtual 10x10 square.

I do not really get your question and the effect you are trying to acheive.
BTW, if my interpretation is correct, you oare trying to do something only if the "drag distance" is grather than a certain amount.
this code below do not use the drag&drop event, but the mouseup, mousedown and mousemove events.
It keeps track of the distance the mouse travels while the left button is pressed.
When the distance is grater than a fixed amount, it changes the mouseCursor(during the dragaction)
When the mouseButton is released, if the dstance traveled is greater than the minimum offset, we perform our fake drop action.
Create a new windows form project and substitute the Form1 autogenerated Class with the one below
Hope this helps.
public partial class Form1 : Form
{
private bool isDragging; //We use this to keep track that we are FakeDragging
private Point startPosition; //The start position of our "Fake" dragging action
private double dragDistance = 0; //The distance(absolute) from the drag action starting point
private const int MINIMUM_DRAG_DISTANCE = 100; //minimum FakeDrag distance.
private Label label1 = new Label();
public Form1()
{
#region Support form generation code
InitializeComponent();
this.label1 = new System.Windows.Forms.Label();
this.label1.AutoSize = true;
this.label1.Location = new System.Drawing.Point(54, 242);
this.label1.Name = "Distance:";
this.label1.Size = new System.Drawing.Size(35, 13);
this.Controls.Add(label1);
this.MouseUp += new System.Windows.Forms.MouseEventHandler(this.Form1_MouseUp);
this.MouseDown += new System.Windows.Forms.MouseEventHandler(this.Form1_MouseDown);
this.MouseMove += new System.Windows.Forms.MouseEventHandler(this.Form1_MouseMove);
#endregion
}
private void Form1_MouseDown(object sender, MouseEventArgs e)
{
//if the mouse button is pressed then
//there's the chanche a dragAction
//is being performed and we take note
//of the position of the click
//(we will use this later on the mouseMove event
//to calculate the distance mouse has traveled
if (e.Button.Equals(MouseButtons.Left))
startPosition = e.Location;
}
private void Form1_MouseUp(object sender, MouseEventArgs e)
{
///at the mouse up event we can execute code that does something
if (isDragging && dragDistance > MINIMUM_DRAG_DISTANCE)
{
MessageBox.Show("we have fakedragged!\nDo something useful here");
//Do your Drag & Drop code here.
}
///but WE MUST signal our system that the Fake Drag has ended
///and reset our support variables.
this.Cursor = Cursors.Default;
isDragging = false;
dragDistance = 0;
}
private void Form1_MouseMove(object sender, MouseEventArgs e)
{
///when the mouse moves we control if the mouse button is still pressed.
///if it is so, we surely are FakeDragging and we set our boolean to true
///(it will be useful in the mouseUP event).
///Then we calculate the absolute distance the mouse has traveld since the
///user has pressed the left mouseButton.
Point currentPosition = e.Location;
if (e.Button.Equals(MouseButtons.Left))
{
isDragging = true;
dragDistance =
Math.Abs(
Math.Sqrt(
(
Math.Pow(
(currentPosition.X - startPosition.X), 2)
+
Math.Pow(
(currentPosition.Y - startPosition.Y), 2)
)));
}
//we set the label text displaying the distance we just calculated
label1.Text =
String.Format(
"Distance: {0}",
dragDistance.ToString());
Application.DoEvents();
///At last, if the distance il greater than our offset, we change the
///mouse cursor(this is not required in a real case scenario)
if (dragDistance > MINIMUM_DRAG_DISTANCE)
this.Cursor = Cursors.Hand;
else
this.Cursor = Cursors.Default;
}
}