Develop Reference

Passing Textbox Values one form to another form in Windows Forms

I am trying to get an input values from user for drawing a Circle ( for this I use Radius input) and a Rectangle ( Edge1 and Edge2 ) inputs. I want to pass these textboxt values on another form to draw them.
How can I move these values to another form in properties section or any solution ideas?
Forms are in the same project by the way.
I defined an interface and implement processes about calculations. My code is below and worked, thank you for responds.
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace Assignment2
{
class CircleShape : Shape, IShape
{
public int radius;
public CircleShape(int radius)
{
this.radius = radius;
}
public double CalculateArea()
{
return Math.PI * radius * radius;
}
public double CalculatePerimeter()
{
return 2 * Math.PI * radius;
}
}
}

One way is to just have a method on your second form that returns any needed details
using (DrawForm drawForm = new DrawForm ())
{
drawForm.ShowDialog(); //will wait for the form to close before continuing
var userResults = drawForm.GetResults(); //returns whatever you need the form to return
return userResults;
}
The above logic only works if the second form is a popup form of sorts. If you want both forms to be persistent, then it's a bit different. You might want to ensure both forms have access to each other. When you create the drawform be sure to save a reference to it. and in the constructor for your drawform add an argument to include the main form.
DrawForm drawForm = new DrawForm(this);//now the forms can talk to each other
in your drawing form when the user hits 'go'
mainForm.TriggerFinishedDrawing(drawingObject);
There are several ways to achieve this sort of behaviour, you just need to decide what sort of flow makes the most sense in your use case

A simple way to pass data from a form to another one is that you can use Application.OpenForms Property.
First, define a TextBox property to access the TextBox instance in Form1.
// Form1.cs
public TextBox TB
{
get { return textBox1; }
set { textBox1 = value; }
}
Then call Application.OpenForms to get Form1 instance.
// Form2.cs
Form1 fr = (Form1)Application.OpenForms["Form1"];
if (fr != null)
{
Form1 f1 = (Form1)fr;
// get text form Form1.textbox1
MessageBox.Show(f1.TB.Text);
}
If Form2 is opened by clicking the button in Form1 and pass the value when Form2 shown, you can achieve it via constructor.
// Form1.cs
private void btnOpenForm2_Click(object sender, EventArgs e)
{
Form2 f2 = new Form2(textBox1.Text);
f2.Show();
}
// From2.cs
string textformForm1;
public Form2(string str)
{
InitializeComponent();
textformForm1 = str;
}
private void btnShowText_Click(object sender, EventArgs e)
{
MessageBox.Show(textformForm1);
}
Similarly, you can also use public properties.
// Form1.cs
private void btnOpenForm2_Click(object sender, EventArgs e)
{
Form2 f2 = new Form2();
f2.TextformForm1 = textBox1.Text;
f2.Show();
}
// Form2.cs
public string TextformForm1 { get; set; }
private void btnShowText_Click(object sender, EventArgs e)
{
MessageBox.Show(TextformForm1);
}

C# - Keeping the values from functions

I want to call a function like Spawn() in this case, but without losing values from it after calling it (for example, I want entityPicture to still be available after I call Spawn(), so I can use it later on MainWindow_KeyDown() function). Same with X and other variables like that.
using System;
using System.Drawing;
using System.Windows.Forms;
namespace EpicGame
{
public partial class MainWindow : Form
{
public MainWindow()
{
InitializeComponent();
}
public void MainWindow_Load(object sender, EventArgs e)
{
int EntityCount = 0;
Background.ImageLocation = "Background.jpg";
Background.SizeMode = PictureBoxSizeMode.AutoSize;
Spawn(600, 600, EntityCount, "Player 1.png"); EntityCount++;
}
// Controls
public void MainWindow_KeyDown(object sender, KeyEventArgs e)
{
if (e.KeyCode == Keys.D) MoveRight();
entityPicture.Location = new Point(X, Y);
}
// Movement
public void MoveRight()
{
X++;
}
// Entity spawning
public void Spawn(int X, int Y, int ID, string Path)
{
PictureBox entityPicture = new PictureBox();
Image Entity = Image.FromFile(Path);
entityPicture.Image = Entity;
entityPicture.SizeMode = PictureBoxSizeMode.AutoSize;
entityPicture.Location = new Point(X, Y);
entityPicture.BackColor = Color.Transparent;
Controls.Add(entityPicture);
entityPicture.BringToFront();
}
private void Background_Click(object sender, EventArgs e)
{
}
}
}

You can declare it public in the form class like:
public partial class MainWindow : Form
{
PictureBox entityPicture = new PictureBox();
}
I don't know the type of entityPicture so just used PictureBox as example, you use the correct type.

Your root issue is one of scope. Have a look at this video, it walks through your exact issue: https://www.youtube.com/watch?v=NemPMKTxM7w
You can technically move entityPicture to the top of the class, however given this appears to be a WinForms window, I would add the PictureBox via the designer so it's only declared once. If you declare it at the class level and reinitialize it in Spawn (i.e. = new PictureBox()) repeatedly, you're going to create a memory leak.

C# Switching between two windows forms

I have two forms. In first I have button forwarding me to second form and hiding the first one with this.Hide();
It looks like this:
Form1Streamer f1 = new Form1Streamer();
f1.Left = this.Left;
f1.Top = this.Top;
f1.Size = this.Size;
f1.Show();
this.Hide();
checkBox1.Checked = false;
It also takes it's position but it's not about it.
In second form I have a button which should after clicking Go back to the hidden form and make it visible again, but I can find no solution how to access it's properity.
I have some ideas but don't really know how to tag it. Any help appreciated.

You need to pass the reference of the first form to the second form in order to call any method of first form. Here is a simple Example that will demonstrate.
Below is my first form class
using System;
using System.Windows.Forms;
namespace Test_Desktop
{
public partial class FirstForm : Form
{
public FirstForm()
{
InitializeComponent();
}
private void showSecondFormButton_Click(object sender, EventArgs e)
{
SecondForm secondform = new SecondForm(this); //Passing the reference of current form i.e. first form
secondform.Show();
this.Hide();
}
}
}
And here is my second form class
using System;
using System.Windows.Forms;
namespace Test_Desktop
{
public partial class SecondForm : Form
{
private FirstForm firstForm = null;
public SecondForm()
{
InitializeComponent();
}
///
/// Overriding constructor
///
public SecondForm(FirstForm firstForm)
{
InitializeComponent();
this.firstForm = firstForm;
}
private void showFirstFormButton_Click(object sender, EventArgs e)
{
if(firstForm!=null)
{
firstForm.Show();
//
//Do some processing
//
this.Dispose();
}
}
}
}

You need the reference of hidden form in the second form. For that, change the constructor of Second form like this
public Form1Streamer(Form firstform)
{
InitilizeComponent();
this.firstForm=firstform;
}
private FirstForm firstForm;
Now you can show the First Form using reference firstForm
In first form, you need to change this code
Form1Streamer f1 = new Form1Streamer();
to
Form1Streamer f1 = new Form1Streamer(this);

Flashing ToolStripButton

I am using a ToolStrip with a number of ToolStripButtons.
What I would like is to be able to flash one of the buttons to get the user's attention.
For example, if they have made changes to information and need to click the Save button.
If this were a normal button I could do this using a Timer and periodically changing the BackColor however this doesn't work with a ToolStrip.
I could create a Renderer subclass and assign it to the ToolStrip but this appears to only get used in specific situations - i.e. it's event driven.
Does anyone have any ideas?

Well, just use a custom renderer so you can change the color of the button's background. With a timer that blinks it. Add a new class to your project and paste this code:
using System;
using System.Drawing;
using System.Collections.Generic;
using System.Windows.Forms;
class BlinkingButtonRenderer : ToolStripProfessionalRenderer {
public BlinkingButtonRenderer(ToolStrip strip) {
this.strip = strip;
this.strip.Renderer = this;
this.strip.Disposed += new EventHandler(strip_Disposed);
this.blinkTimer = new Timer { Interval = 500 };
this.blinkTimer.Tick += delegate { blink = !blink; strip.Invalidate(); };
}
public void BlinkButton(ToolStripButton button, bool enable) {
if (!enable) blinkButtons.Remove(button);
else blinkButtons.Add(button);
blinkTimer.Enabled = blinkButtons.Count > 0;
strip.Invalidate();
}
protected override void OnRenderButtonBackground(ToolStripItemRenderEventArgs e) {
var btn = e.Item as ToolStripButton;
if (blink && btn != null && blinkButtons.Contains(btn)) {
Rectangle bounds = new Rectangle(Point.Empty, e.Item.Size);
e.Graphics.FillRectangle(Brushes.Black, bounds);
}
else base.OnRenderButtonBackground(e);
}
private void strip_Disposed(object sender, EventArgs e) {
blinkTimer.Dispose();
}
private List<ToolStripItem> blinkButtons = new List<ToolStripItem>();
private bool blink;
private Timer blinkTimer;
private ToolStrip strip;
}
Sample usage in a form with a Toolstrip containing a button:
public partial class Form1 : Form {
public Form1() {
InitializeComponent();
blinker = new BlinkingButtonRenderer(toolStrip1);
}
private void toolStripButton1_Click(object sender, EventArgs e) {
blink = !blink;
blinker.BlinkButton(toolStripButton1, blink);
}
private bool blink;
private BlinkingButtonRenderer blinker;
}

Draw on a form by a separate thread

I'm trying to build a multithreaded game where I have a separate thread for painting on the form which is not the main thread. this brings us to thread-safe technics which I've read many articls about, but I'm not really sure I got it correctly.
my problem is that I have a structure where every data object is painting it self on the form so I didn't figure out how to implement it.
this is a snippet of my working mono-thread code:
public partial class Form1 : Form
{
GameEngine Engine;
public Form1()
{
InitializeComponent();
Engine = new GameEngine();
}
protected override void OnPaint(PaintEventArgs e)
{
Engine.Draw(e.Graphics);
}
}
class GameEngine
{
Maze Map;
List<Player> Players;
public void Draw(Graphics graphics)
{
Map.Draw(graphics);
foreach (var p in Players)
{
p.Draw(graphics);
}
}
}
so please can anyone give me a hint or a link to good article helping me to learn how to separate the drawing on an another thread?.
[Edit]
I managed to implement what I intended to do
and this is how I coded it
protected override void OnPaint(PaintEventArgs e)
{
formGraphics = e.Graphics;
DisplayThread = new Thread(new ThreadStart(Draw));
DisplayThread.Start();
}
private void Draw()
{
if (this.InvokeRequired)
{
this.Invoke(new DrawDelegate(this.Draw));
}
else
{
Engine.Draw(formGraphics);
}
}
but I got an ArgumentException : Parameter is not valid
would you please point to the error in that code

I think you will need to draw to a Bitmap, then in the OnPaint Method, draw that bitmap to the window. I will demonstrate in a moment.
As Hans pointed out, in the OnPaint method you are setting
formGraphics = e.Graphics;
but at the end of the method e.Graphics is disposed, so you can't use it anymore, if your code got to
Engine.Draw(formGraphics);
you would get an exception.
So basically you need to have a global
Bitmap buffer = new Bitmap(this.Width, this.Height)
in your asynced thread you would invoke your drawing to that Bitmap you can use
Graphics g=Graphics.FromBitmap(buffer);//
To get a graphics object, but remember you have to
g.Dispose()
it or wrap it in a
using (Graphics g=Graphics.FromBitmap(buffer))
{
//do something here
}
I am going to play with it for a few moments and see if I can get you a working sample
EDIT Here's your working sample.
I started a new form and tossed a button on it. I changed the mainform backgroundimagelayout to none.
I think you need to be using .net 4.0 or better, if not using this, let me know I can change it to match your version... I think.
//you need this line to use the tasks
using System.Threading.Tasks;
namespace WindowsFormsApplication1
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
public void Draw()
{
Bitmap buffer;
buffer = new Bitmap(this.Width, this.Height);
//start an async task
Task.Factory.StartNew( () =>
{
using (Graphics g =Graphics.FromImage(buffer))
{
g.DrawRectangle(Pens.Red, 0, 0, 200, 400);
//do your drawing routines here
}
//invoke an action against the main thread to draw the buffer to the background image of the main form.
this.Invoke( new Action(() =>
{
this.BackgroundImage = buffer;
}));
});
}
private void button1_Click(object sender, EventArgs e)
{
//clicking this button starts the async draw method
Draw();
}
}
}