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Calling a non static void method from another class in c#

Hey I got Code Written in Class Form1 And Form2. I want to call the method openkindForm() from Form2. I tried every soloution I found. I got this one at the moment which is not working it gives me a System.NullReferenceException. I do not know why it isnt working. I tried it so long but whatever I do it will not workout somehow. I would be thankfull for an answer.
Kind regards
First Class
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
namespace FBDP00
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
submenupanel.Visible = false;
}
private void funktionenSM_Click(object sender, EventArgs e)
{
switch (submenupanel.Visible)
{
case true:
submenupanel.Visible = false;
break;
case false:
submenupanel.Visible = true;
break;
}
}
public void neuepruefungSm_Click(object sender, EventArgs e)
{
submenupanel.Visible = false;
openkindForm(new Form2());
}
public Form activeForm = null;
public void openkindForm(Form childForm)
{
if (activeForm != null)
{
activeForm.Close();
}
activeForm = childForm;
childForm.TopLevel = false;
childForm.FormBorderStyle = FormBorderStyle.None;
childForm.Dock = DockStyle.Fill;
backgroundPanel.Controls.Add(childForm);
childForm.Show();
}
}
}
Class 2
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using static FBDP00.Form1;
namespace FBDP00
{
public partial class Form2 : Form
{
public Form1 testform;
public Form2()
{
InitializeComponent();
}
private void button3_Click(object sender, EventArgs e)
{
}
private void button2_Click(object sender, EventArgs e)
{
}
private void funktionenSM_Click(object sender, EventArgs e)
{
}
public void baukontrolleb_Click(object sender, EventArgs e)
{
testform.openkindForm(new Form3());
}
}
}

In Form2 you have defined a variable for Form1 (testform), but you don't set this anywhere. So this is why you get a Null reference error when you try to use it, because it is null!
So when you create your Form2 then you need to set this value. In your case, maybe in the constructor like this.
public Form1 testform;
private Form2(Form1 f1)
{
InitializeComponent();
testform = f1;
}
Then call it like this:
public void neuepruefungSm_Click(object sender, EventArgs e)
{
submenupanel.Visible = false;
openkindForm(new Form2(this));
}
However, looking at your openkindForm method, it seems to me that this really has nothing to do with Form1, and shares no variables, so should not be in this class.
You should either make this static (together with the activeForm variable), or make it a Singleton class instead. But certainly this should be a separate class.

Serial Port Data Received Event accessed from Multiple forms

I'm trying to make a windows form application in Visual Studio in C# and the purpose is to be able to communicate with an Arduino microcontroller. Right now I have 2 forms (Form1 and Form2) and I need to send and receive data from both windows to the microcontroller. I have defined a class SerialComms.cs in which there I start my serialPort and I have been able to send messages from both forms to the Arduino.
The problem is I don't know how to go about to receiving data from the Arduino as soon as the data is received. If I were to create the serialPort from one of the forms i would be able to create a function for DataReceived that will run anytime data is received but I don't know how to do that when I start my serialPort from a class. Any help?
Here is my code for both forms and my serialComms class:
Form1
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.IO.Ports;
using System.IO;
namespace Test_Comms
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void Form1_Load(object sender, EventArgs e)
{
connectToArduino();
}
void connectToArduino()
{
try { SerialComms.SerialPort.Close(); }
catch { }
getAvailablePorts();
for (int i = 0; i < COMcomboBox.Items.Count; i++)
{
string inputMsg = "None";
string commport = COMcomboBox.GetItemText(COMcomboBox.Items[i]);
//Wait for Arduino message sent
//If not receieved go to next port
SerialComms.SerialPort.PortName = commport;
SerialComms.SerialPort.BaudRate = 9600;
SerialComms.SerialPort.Open();
try { SerialComms.SerialPort.Open(); }
catch { }
int counter1 = 0;
while (counter1 < 100)
{
inputMsg = SerialComms.SerialPort.ReadLine();
try { inputMsg = SerialComms.SerialPort.ReadLine(); }
catch { }
counter1++;
if (inputMsg == "Arduino")
{
counter1 = 1000;
}
}
if (inputMsg != "Arduino")
{
try { SerialComms.SerialPort.Close(); }
catch { }
}
else
{
i = COMcomboBox.Items.Count;
SerialComms.SerialPort.WriteLine("Connection Established");
toolStripStatusLabel1.Text = "Connected";
break;
}
}
}
void getAvailablePorts()
{
COMcomboBox.Items.Clear();
String[] ports = SerialPort.GetPortNames();
COMcomboBox.Items.AddRange(ports);
}
private void button1_Click(object sender, EventArgs e)
{
SerialComms.SerialPort.WriteLine("LED ON");
}
private void button2_Click(object sender, EventArgs e)
{
SerialComms.SerialPort.WriteLine("LED OFF");
}
private void button3_Click(object sender, EventArgs e) //Opens second form
{
Form2 settingsForm = new Form2();
settingsForm.ShowDialog();
}
}
}
Form2
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.IO.Ports;
using System.IO;
namespace Test_Comms
{
public partial class Form2 : Form
{
public static string text = "Test text";
public Form2()
{
InitializeComponent();
}
private void button1_Click(object sender, EventArgs e)
{
SerialComms.SerialPort.WriteLine("LED ON");
}
private void button2_Click(object sender, EventArgs e)
{
SerialComms.SerialPort.WriteLine("LED OFF");
button2.Text = text;
}
private void Form2_Load(object sender, EventArgs e)
{
}
}
}
SerialComms.cs
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.IO.Ports;
using System.IO;
namespace Test_Comms
{
public static class SerialComms
{
//public static delegate void DataReceivedEventHandler(object sender, ReceivedEventArgs e);
//public static event DataReceivedEventHandler DataReceived;
private static SerialPort _serialPort = new SerialPort();
public static SerialPort SerialPort
{
get { return _serialPort; }
set { _serialPort = value; }
}
}
}

l versC# multithread issue

I cannot get the ui thread to update the ui while the file copy thread is running. My end goal is to have the animation continue to rotate until the large file copy finally completes to let the user know that the program is not frozen. It's a very simple server to server file copy program.
Can someone tell me what I'm doing wrong?
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.Threading;
using System.IO;
using System.Threading.Tasks;
namespace WindowsFormsApplication1
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void ResetProgress()
{
lblStep1.Image = null;
}
private void SetupProgress()
{
lblStep1.Image = global::animation1.Properties.Resources.animation;
}
private void fileCopy()
{
File.Copy("large file source", "large file destination", true);
}
private void Form1_Load(object sender, EventArgs e)
{
lblStep1.Image = global::animation1.Properties.Resources.animation;
}
private async void button1_Click(object sender, EventArgs e)
{
SetupProgress();
await Task.Run(() => fileCopy());
ResetProgress();
}
private void btnStop_Click(object sender, EventArgs e)
{
// unhandled currently
}
}
}
* Original version *
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.Threading;
using System.IO;
using System.Threading.Tasks;
namespace WindowsFormsApplication1
{
public partial class Form1 : Form
{
private Thread workItemsProducerThread;
private Thread workItemsCopyThread;
public Form1()
{
InitializeComponent();
}
private void ResetProgress()
{
lblStep1.Image = null;
}
private void SetupProgress()
{
this.BeginInvoke((MethodInvoker)delegate ()
{
lblStep1.Image = global::animation1.Properties.Resources.animation;
});
}
private void fileCopy()
{
File.Copy("Large file source", "Large file destination", true);
this.BeginInvoke((MethodInvoker)delegate ()
{
MessageBox.Show("Done");
});
}
private void Form1_Load(object sender, EventArgs e)
{
lblStep1.Image = global::animation1.Properties.Resources.animation;
}
private void btnStart_Click(object sender, EventArgs e)
{
this.workItemsProducerThread = new Thread(new ThreadStart(this.SetupProgress));
this.workItemsProducerThread.IsBackground = true;
this.workItemsProducerThread.Start();
this.SetupProgress();
this.workItemsCopyThread = new Thread(new ThreadStart(this.fileCopy));
this.workItemsCopyThread.IsBackground = true;
this.workItemsCopyThread.Start();
while (workItemsCopyThread.IsAlive)
{
Thread.Sleep(1000); // wait
}
MessageBox.Show("Done");
}
private void btnStop_Click(object sender, EventArgs e)
{
if (this.workItemsProducerThread != null)
{
this.workItemsProducerThread.Abort();
lblStep1.Image = global::animation1.Properties.Resources.animation;
}
}
private void btnTest_Click(object sender, EventArgs e)
{
fileCopy();
}
}
}

Don’t sleep in your click handler. That freezes the UI thread. Just let the clock handler exit. In your file copy thread, when the copy is don’t. Use Invoke(or BeginInvoke) to cause the done messagebox to pop up on the UI thread.

Try this oldy style
private void SetupProgress()
{
Invoke((MethodInvoker) delegate
{
lblStep1.Image = global::animation1.Properties.Resources.animation;
});
}
private Thread TDoSomeWork()
{
var t = new Thread(() => DoSomeWork());
t.Start();
return t;
}
TDoSomeWork();

Visual Studio 2010 says “Expected class, delegate, enum, interface or struct”

When trying to write something to check whether a number is odd or even (C#), Visual Studio 2010 displays the error message I've mentioned above...
This is 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;
namespace WindowsFormsApplication2
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void chk_Click(object sender, EventArgs e)
{
int x = Convert.ToInt32(num.Text);
if (x%2 == 0)
{
chkd.Text = "Even";
}
else
{
chkd.Text = "Odd";
}
}
}
private void num_TextChanged(object sender, EventArgs e)
{
}
}

num_TextChanged is a method that is outside your class. The only things that can appear inside a namespace scope are, per the error message, a class, delegate, enum, interface or struct.
I expect you meant this to be inside the Form1 class, so you should move it:
namespace WindowsFormsApplication2
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void chk_Click(object sender, EventArgs e)
{
int x = Convert.ToInt32(num.Text);
if (x%2 == 0)
{
chkd.Text = "Even";
}
else
{
chkd.Text = "Odd";
}
}
private void num_TextChanged(object sender, EventArgs e)
{
}
}
}

Add one more
}
which close /end namespace of form class

Why won't my textbox update when I am doing the exact same thing just with a different function?

My TextBox won't update! I am using it as a Log to update what other things are doing...
Form 1 code:
using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;
using System.IO;
using System.Data.OleDb;
using System.Collections.Specialized;
using System.Text;
delegate void logAdd(string message);
namespace LCR_ShepherdStaffupdater_1._0
{
public partial class Main : Form
{
public Main()
{
InitializeComponent();
}
public void logAdd(string message)
{
this.Log.Items.Add(message); // Doesnt add to textbox
this.Log.Items.Add("This won't update the textbox!!! Why?"); // Doesnt add to textbox
}
private void exitProgramToolStripMenuItem_Click(object sender, EventArgs e)
{
Application.Exit();
}
private void aboutToolStripMenuItem1_Click(object sender, EventArgs e)
{
Form aboutBox = new AboutBox1();
aboutBox.ShowDialog();
}
private void settingsToolStripMenuItem_Click(object sender, EventArgs e)
{
}
private void settingsToolStripMenuItem1_Click(object sender, EventArgs e)
{
settingsForm.settings.ShowDialog();
}
private void synchronize_Click(object sender, EventArgs e)
{
this.Log.Items.Add("This WILL update the textbox. It is exactly the same as the other one..."); // This will add to the textbox
DatabaseHandling.createDataSet();
}
}
public class settingsForm
{
public static Form settings = new Settings();
}
}
My Logging Class code:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace LCR_ShepherdStaffupdater_1._0
{
public class Logging
{
static Main mainClass = new Main();
static logAdd logAddDelegate;
public static void updateLog(string message)
{
logAddDelegate = mainClass.logAdd;
logAddDelegate(message);
}
}
}
I am just completely stumped....does anyone know how I can fix the logAdd function so I can get my textbox log to finally update?
EDIT:
I finally got it to work, here was the fix:
Form1 Code
using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;
using System.IO;
using System.Data.OleDb;
using System.Collections.Specialized;
using System.Text;
delegate void logAdd(string message);
namespace LCR_ShepherdStaffupdater_1._0
{
public partial class Main : Form
{
public Main()
{
InitializeComponent();
}
public void add(string message)
{
this.Log.Items.Add(message);
}
public void logAdd(string message)
{
Log.Invoke(new logAdd(add), new object[] { message });
}
private void exitProgramToolStripMenuItem_Click(object sender, EventArgs e)
{
Application.Exit();
}
private void aboutToolStripMenuItem1_Click(object sender, EventArgs e)
{
Form aboutBox = new AboutBox1();
aboutBox.ShowDialog();
}
private void settingsToolStripMenuItem_Click(object sender, EventArgs e)
{
}
private void settingsToolStripMenuItem1_Click(object sender, EventArgs e)
{
settingsForm.settings.ShowDialog();
}
private void synchronize_Click(object sender, EventArgs e)
{
logAdd("this works");
}
}
public class settingsForm
{
public static Form settings = new Settings();
}
}
Logging Code:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace LCR_ShepherdStaffupdater_1._0
{
public class Logging
{
static Main mainClass = new Main();
static logAdd logAddDelegate;
public static void updateLog(string message)
{
logAddDelegate = mainClass.logAdd;
logAddDelegate(message);
}
}
}
Well...I can tell that is a really bad way to do it...but until I find a true fix as long as it works im happy. Thanks for the help guys!

From the code you posted your static Logger class is creating a new instance of the Main form. which is different than the one your running on the UI.
Overall this isn't a very good design pattern. write a comment if you want me to elaborate and give a sample.

What thread are you calling Logging.updateLog() from? If it's not the UI thread, I could see that the TextBox wouldn't get updated in that case. If you try calling logAdd() from synchronize_Click() (assuming that this is called from the UI thread based on the name), does it work then?

the synchronize_click is run on the instance of the main form that is running. The logadd function is run on a seperate main form that you create in the logging code. For this to work, you need to pass your existing main form into the log code so that it updates the text box you can see, not the extra text box you don't.

I had a problem similar once before, it was solved by calling .Invalidate() on the text box after writing to it.
You could also check your message is actually getting to the textbox with:
debug.WriteLine( this.Log.Items( this.Log.Items.Count-1));
Hope that helps you.