How to modify label text in C# forms - c#

(I am very new to C#) I am creating a forms application, and the purpose is to get a string from a Web API, then put that text onto a label. I have successfully gotten the data from the Web, but when I try to update the label, I have no luck.
I have debugged and found that my method inside my class Is executing, but just not setting the label's text. As you can see below, I tried to use this.resultLabel.text = str;. Here's the classes:
Program.cs (not the form cs file)
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.Net.Http;
using System.Net;
using System.IO;
namespace WebsiteAPITest
{
static class Program
{
/// <summary>
/// The main entry point for the application.
/// </summary>
[STAThread]
static void Main()
{
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
Application.Run(new Form1());
}
}
class PostManager
{
public void setupClient()
{
HttpWebRequest WebReq = (HttpWebRequest)WebRequest.Create(string.Format("https://yakovliam.com/phpApi/csTest.php"));
WebReq.Method = "GET";
HttpWebResponse WebResp = (HttpWebResponse)WebReq.GetResponse();
string respStr;
using (Stream stream = WebResp.GetResponseStream()) //modified from your code since the using statement disposes the stream automatically when done
{
StreamReader reader = new StreamReader(stream, System.Text.Encoding.UTF8);
respStr = reader.ReadToEnd();
}
MessageBox.Show(respStr);
Form1 form = new Form1();
form.SetResultLabel(respStr);
}
}
}
Actual form class (Form1.cs)
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 WebsiteAPITest
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void Form1_Load(object sender, EventArgs e)
{
}
private void GetButton_Click(object sender, EventArgs e)
{
PostManager postManager = new PostManager();
postManager.setupClient();
}
public void SetResultLabel(string str)
{
this.resultLabel.Text = str;
this.resultLabel.Refresh();
}
}
proof of label name:

Inside setupClient you call Form1 form = new Form1(); that creates a second Form1 which you never display, then you call SetResultLabel(respStr) inside this second form you never display, then you leave the method and discard it.
If you want to call SetResultLabel of your calling form, you have to pass the calling form to setupClient:
public void setupClient(Form1 callingForm)
{
...
callingForm.SetResultLabel(respStr);
Then inside your Form1:
postManager.setupClient(this);
It's quite dangerous to pass forms to other methods; a better design is to have the other method return data to your form:
public string setupClient()
{
...
return respStr;
}
And inside Form1:
SetResultLabel(postManager.setupClient());

Related

How to use created Instance on all forms / How to make my instance public C# windowsforms

Hello it is probably easy question for you, I'm a beginner and I'm making my own simple game and I want to use a Class:Gamer, which I want to initialize in MainWindow(Form1.cs) from a save file. From then, I want to use it on another Forms aswell, but somehow I can't make the instance go public.
Could you tell me what I'm doing wrong? Or is there another way how to solve this?
Thank you :)
Code on 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.Drawing.Text;
using System.IO;
namespace THE_GAME
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
public static Gamer Player;
private void MainWindow_Load(object sender, EventArgs e)
{
//load from savefile lvl;hp;money;gun;armor,name
string allData = File.ReadAllText("../../saveFile/save.txt");
string[] dataFromSave = new string[5];
dataFromSave = allData.Split(';');
Player = new Gamer(dataFromSave[0], dataFromSave[1], dataFromSave[2], dataFromSave[3], dataFromSave[4], dataFromSave[5]);
}
}
}
Code on secondForm2:
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.Drawing.Text;
namespace THE_GAME
{
public partial class Statistics : Form1
{
public Statistics()
{
InitializeComponent();
}
private void Statistics_Load(object sender, EventArgs e)
{
//labels stats
labelName.Text = Form1.Player.GetName();
labelHealth.Text = Form1.Player.GetHealth().ToString();
labelMoney.Text = Form1.Player.GetMoney().ToString();
}
private void buttonBack_Click(object sender, EventArgs e)
{
MainMenu menu = new MainMenu();
menu.Show();
this.Close();
}
}
}
Thank you for your time.
To get at the Gamers Player object from a different Form just do
Form1.Player;
ie
var nam = Form1.Player.Name;
Form1.Player.Die();
etc
PS As I said in a comment - its extremely odd to dereive a form of yours from another one of your forms. Like this
public partial class Statistics : Form1

An unhandled exception of type 'System.StackOverflowException' occurred in WindowsFormsApplication3.exe [duplicate]

This question already has answers here:
Why does Property Set throw StackOverflow exception?
(3 answers)
Closed 2 years ago.
I'm using C# to develop a windows forms application and I required to store certain values (Ex: UserID and Role), in order to use them again in various forms throughout the application.
The User ID and the Role will be changed with each login.
So tried using static classes.
To test it out first, I did the following.
Created "Form1" with a textbox and a button.
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 WindowsFormsApplication3
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void btnDisplay_Click(object sender, EventArgs e)
{
common.text = textBox1.Text;
Form2 obj = new Form2();
obj.Show();
}
}
}
Then created "Form 2" with only a label.
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 WindowsFormsApplication3
{
public partial class Form2 : Form
{
public Form2()
{
InitializeComponent();
}
private void Form2_Load(object sender, EventArgs e)
{
label1.Text = common.text;
}
}
}
And to interconnect these two forms, created the following class.
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace WindowsFormsApplication3
{
public static class common
{
public static string text
{
get
{
return text;
}
set
{
text = value;
}
}
}
}
The purpose was to see if the label text on form2 would change when clicked on the button after entering text into the textbox in form1.
When running the code, the following error was thrown. Displays that this is thrown from the "set" method of the class.
An unhandled exception of type 'System.StackOverflowException' occurred in WindowsFormsApplication3.exe
If anyone could provide any clarity on this, it would be highly appreciated.
Thanks in advance.
Your set method is calling itself.
You need to add private string and change it and then return the changes via get.
Try this:
private static string _text;
public static string text
{
get
{
return _text;
}
set
{
_text = value;
}
}

Passing txtBox values between forms

I have always had trouble with this issue, i think i need to learn how it works, i have FormMain (my main form) and a second form (FormAddUrls) when i open form2 (FormAddUrls) i want to pass the multitextbox value back to the main form (FormMain)
I know in VB it's as simple as saying: FormMain.txtBoxUrls.Text = finalOutput; but not as easy in C#.
(form1) - FormMain
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.IO;
using System.Linq;
using System.Net;
using System.Windows.Forms;
using WraithProjectCreator;
using IronPdf;
using System.Text;
namespace GSAProjectCreator
{
public partial class FormMain : Form
{
private IniParser m_Parser = null;
public FormMain()
{
InitializeComponent();
}
private void btnShowUrlsForm_Click(object sender, EventArgs e)
{
FormAddUrls fau = new FormAddUrls();
fau.Show();
}
}
}
(form2) - FormAddUrls
using GSAProjectCreator;
using System;
using System.Text;
using System.Windows.Forms;
namespace WraithProjectCreator
{
public partial class FormAddUrls : Form
{
public FormAddUrls()
{
InitializeComponent();
}
private void btnAddUrls_Click(object sender, EventArgs e)
{
StringBuilder builder = new StringBuilder();
builder.Append("{");
foreach (string line in txtBoxURLsMass.Lines)
{
//Helpers.returnMessage(line);
builder.Append(line + "|");
}
builder.Append("}");
string finalOutput = "";
if (builder.ToString().Contains("|}")) {
finalOutput = builder.ToString().Replace("|}", "}");
}
//FormMain.txtBoxUrls.Text = finalOutput;
this.Close();
}
}
}
I have ommited a lot of form1's code to leave the basic structure, i'm trying to pass back finalOutput from form2 to form1 (the txtBoxUrls.Text) text box, any help would be appreciated.
It depends on how you want to use the main form - you could have a static property which you could set (which would update the text for all main form instances).
If you only have one main form, and have a reference to it when you create the FormAddUrls object then you should just change the constructor to accept a MainForm (or as generic a type as possible), store the reference as a field and update the property on it when the button is clicked:
public partial class FormAddUrls : Form
{
private readonly Form _parentForm;
public FormAddUrls(MainForm parent)
{
_parentForm = parent;
InitializeComponent();
}
private void btnAddUrls_Click(object sender, EventArgs e)
{
StringBuilder builder = new StringBuilder();
builder.Append("{");
foreach (string line in txtBoxURLsMass.Lines)
{
//Helpers.returnMessage(line);
builder.Append(line + "|");
}
builder.Append("}");
string finalOutput = "";
if (builder.ToString().Contains("|}")) {
finalOutput = builder.ToString().Replace("|}", "}");
}
if(_parentForm != null)
_parentForm.txtBoxUrls.Text = finalOutput;
this.Close();
}
}

Change button text from another class in another namespace

I have a problem changing text from another class in another namespace. I have the first Form1 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;
using System.Runtime.InteropServices;
namespace WindowsFormsApplication1
{
public partial class Form1 : Form
{
static Form1 mainForm;
[DllImport("kernel32.dll", SetLastError = true)]
[return: MarshalAs(UnmanagedType.Bool)]
static extern bool AllocConsole();
public static String LinkToApi = "http://google.com/api/";
public static Comunicator comunicator;
public static int debug = 5;
public Form1()
{
InitializeComponent();
AllocConsole(); // allow console
if(Form1.debug >= 3) Console.WriteLine("Application started");
comunicator = new Comunicator();
mainForm = this;
}
private void TestButton_Click(object sender, EventArgs e)
{
TestButton.Text = "Loading";
comunicator.TestConnection();
}
}
}
and this Comunicator class
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Net;
using System.Collections.Specialized;
using System.Windows.Forms;
using System.Runtime.InteropServices;
using System.IO;
using System.Threading;
namespace WindowsFormsApplication1
{
public class Comunicator
{
private String action = "idle";
public static Thread Start(Action action)
{
Thread thread = new Thread(() => { action(); });
thread.Start();
return thread;
}
public Comunicator()
{
}
public void TestConnection()
{
if (Form1.debug >= 3) Console.WriteLine("Testing connection");
// thread test
Start(new Action(ApiTest));
}
public void ApiTest()
{
if (Form1.debug >= 3) Console.WriteLine("API test begin");
// Create a request for the URL.
WebRequest request = WebRequest.Create("http://www.bogotobogo.com/index.php");
// If required by the server, set the credentials.
request.Credentials = CredentialCache.DefaultCredentials;
// Get the response.
HttpWebResponse response = (HttpWebResponse)request.GetResponse();
// Display the status.
Console.WriteLine(response.StatusDescription);
// Get the stream containing content returned by the server.
Stream dataStream = response.GetResponseStream();
// Open the stream using a StreamReader for easy access.
StreamReader reader = new StreamReader(dataStream);
// Read the content.
string responseFromServer = reader.ReadToEnd();
// Display the content.
Console.WriteLine(responseFromServer);
// Cleanup the streams and the response.
reader.Close();
dataStream.Close();
response.Close();
// Console.Read();
if (Form1.debug >= 3) Console.WriteLine("API test end");
// Form1.StaticTestButton.Text = "Loaded"; <---- CHANGE HERE
}
}
}
which is not even a form class (I want to keep everything nice and clean). I want to change the TestButton text into "LOADED" but i get an error when I try to do that as if Form1.TestButton does not exist in Comunicator class.
I have tried to instantiate the class, I made a couple of variables static ... nothing, still getting error.
What is the problem? How may I solve this?
The request must be asynchronous, that's why I am using threads.
You should separate concerns, and you shouldn't communicate with UI in class which is not related to UI.
You should rewrite your code.
But as quick fix you should do the following.
In class Comunicator, you can do such field.
private readonly Action<string> _notifySimpleMessageAction;
Then add to Communicator constructor parameter notifyFunction. Code in constructor:
_notifySimpleMessageAction = notifyFunction
After that you should create Communicator in following manner:
communicator = new Communicator((notification)=>
{
StaticTestButton.BeginInvoke((MethodInvoker)(() => StaticTestButton.AppendText(notification)));
});
Then at the end of your method you should do
_notifySimpleMessageAction("Loaded")
Controller class:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
namespace ControllerDemonstrator
{
public class Controller
{
public event EventHandler CommunicatorDataLoaded;
public event EventHandler FormTestConnection;
private Form1 _form;
private Communicator _communicator;
public Form1 MainForm
{
get { return _form; }
}
public Controller()
{
_form = new Form1(this);
_form.TestConnection += _form_TestConnection;
_form.FormClosed += _form_FormClosed;
_communicator = new Communicator(this);
_communicator.DataLoaded += _communicator_DataLoaded;
}
public void Start()
{
_form.Show();
}
void _form_FormClosed(object sender, System.Windows.Forms.FormClosedEventArgs e)
{
// put any code to clean up the communicator resources (if needed) here
// --------------------------------------------------------------------
_communicator = null;
// Then exit
// ---------
Application.Exit();
}
private void _communicator_DataLoaded(object sender, EventArgs e)
{
if (null != CommunicatorDataLoaded)
{
CommunicatorDataLoaded(sender, e);
}
}
private void _form_TestConnection(object sender, EventArgs e)
{
if (null != FormTestConnection)
{
FormTestConnection(sender, e);
}
}
}
}
Basic form with one button (_testButton):
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 ControllerDemonstrator
{
public partial class Form1 : Form
{
public event EventHandler TestConnection;
public Form1(Controller controller)
{
InitializeComponent();
controller.CommunicatorDataLoaded += controller_CommunicatorDataLoaded;
}
void controller_CommunicatorDataLoaded(object sender, EventArgs e)
{
_testButton.Text = "Loaded";
}
private void _testButton_Click(object sender, EventArgs e)
{
if (null != TestConnection)
{
TestConnection(this, new EventArgs());
}
}
}
}
Communicator class (everything has been stripped out, you will need to add in your logic):
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace ControllerDemonstrator
{
public class Communicator
{
public event EventHandler DataLoaded;
public Communicator(Controller controller)
{
controller.FormTestConnection += controller_FormTestConnection;
}
private void controller_FormTestConnection(object sender, EventArgs e)
{
// put your code that does the connection here
// -------------------------------------------
if (null != DataLoaded)
{
DataLoaded(this, new EventArgs());
}
}
}
}
And in your Program.cs (assuming that is how you are starting your application):
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using System.Windows.Forms;
namespace ControllerDemonstrator
{
static class Program
{
/// <summary>
/// The main entry point for the application.
/// </summary>
[STAThread]
static void Main()
{
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
Controller c = new Controller();
Application.Run(c.MainForm);
}
}
}
With this kind of design, the communicator doesn't know about the form and vice verse. You can expand it out to have different kind's of communicators/forms/etc and have the controller keep track of everything. It is also much easier to test code like this as you can test each separate piece on it's own since they don't depend on each other. This is a quick and dirty implementation. Do some research on the Model View Controller design pattern (not Microsoft MVC for asp.Net, but the actual design pattern). It is more code up-front to code an application with the MVC design pattern but it makes it easier to test and more maintainable.

Splash screen doesn't hide - using Microsoft.VisualBasic library

I have 2 forms. Form1 (with code below) and Splash (just default form for test).
My problem is that after application run the Splash doesn't hide. Main form is loaded but Splash is still not closed.
The Form1 code:
using System;
using System.Collections.Generic;
using System.Windows.Forms;
using Microsoft.VisualBasic.ApplicationServices;
namespace WindowsFormsApplication2
{
class Program : WindowsFormsApplicationBase
{
/// <summary>
/// The main entry point for the application.
/// </summary>
[STAThread]
static void Main(string[] args)
{
//Application.EnableVisualStyles();
//Application.SetCompatibleTextRenderingDefault(false);
//Application.Run(new Form1());
// Show Form in Single-instance mode
var prg = new Program();
prg.EnableVisualStyles = true;
prg.IsSingleInstance = true;
prg.MinimumSplashScreenDisplayTime = 1000;
prg.SplashScreen = new Splash();
prg.MainForm = new Form1();
prg.Run(args);
}
}
}
You must add reference to Microsoft.VisualBasic to work of this.
Splash form code:
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
namespace WindowsFormsApplication2
{
public partial class Splash : Form
{
public Splash()
{
InitializeComponent();
}
}
}
Thank you in advance for your help.
Ah you're using the Visual Basic Appplication Framework to run the splash screen?
Try this.
This is from a quick Forms application - note that I have left all names and namespace as default, so you may need to change this for your code. The project has two forms only. Form2 is the splash screen. I embedded a background image on it in order to ensure that it popped up okay and that I could differentiate it from Form1.
I added a reference to .NET Microsoft.VisualBasic into my project.
This is from the program.cs file
using System;
using System.Collections.Generic;
using System.Linq;
using System.Windows.Forms;
using Microsoft.VisualBasic.ApplicationServices;
namespace WindowsFormsApplication1
{
static class Program
{
[STAThread]
static void Main(string[] args)
{
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
new MyApp().Run(args);
}
}
public class MyApp : WindowsFormsApplicationBase
{
protected override void OnCreateSplashScreen()
{
this.SplashScreen = new Form2();
}
protected override void OnCreateMainForm()
{
// Do your initialization here
//...
System.Threading.Thread.Sleep(5000); // Test
// Then create the main form, the splash screen will automatically close
this.MainForm = new Form1();
}
}
}
I know that is different to wht you're using but it seems to work.

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