Develop Reference

Adding a new line when checking a checkbox

When I click on a checkbox I want the next checkbox information to be displayed on a new line, I know how to do this with "\r\n" however when unchecking the box and rechecking the box, it adds a new line above the text moving the original text down by 1 line. https://imgur.com/a/IHDDG85
I've tried "\r\n" and Environment.NewLine
private void chkHamburger_CheckedChanged(object sender, EventArgs e)
{
if (chkHamburger.Checked == true)
{
txtHamburger.Enabled = true;
txtHamburger.Text = "";
txtHamburger.Focus();
txtOrder.Text += ("Hamburger");
}
else
{
txtHamburger.Enabled = false;
txtHamburger.Text = "0";
}
if (chkHamburger.Checked == false)
{
txtOrder.Text = txtOrder.Text.Replace("Hamburger", "");
}
}
private void chkCheeseBurger_CheckedChanged(object sender, EventArgs e)
{
if (chkCheeseBurger.Checked == true)
{
txtCheeseBurger.Enabled = true;
txtCheeseBurger.Text = "";
txtCheeseBurger.Focus();
txtOrder.Text += ("Cheese Burger");
}
else
{
txtCheeseBurger.Enabled = false;
txtCheeseBurger.Text = "0";
}
if (chkCheeseBurger.Checked == false)
{
txtOrder.Text = txtOrder.Text.Replace("Cheese Burger", "");
}
}
I want the text of a checkbox to be displayed on a new line but when rechecking the box a whitespace should not appear above it.

I suggest you to use a List<string> where you add or remove your orders. Then it is easy to rebuild the txtOrder data with a single line of code using string.Join
List<string> orders = new List<string>();
private void chkHamburger_CheckedChanged(object sender, EventArgs e)
{
txtHamburger.Enabled = chkHamburger.Checked;
if (chkHamburger.Checked)
{
txtHamburger.Text = "";
txtHamburger.Focus();
orders.Add("Hamburger");
}
else
{
txtHamburger.Text = "0";
orders.Remove("Hamburger");
}
UpdateOrders();
}
private void chkCheeseBurger_CheckedChanged(object sender, EventArgs e)
{
txtCheeseBurger.Enabled = chkCheeseBurger.Checked;
if (chkCheeseBurger.Checked)
{
txtCheeseBurger.Text = "";
txtCheeseBurger.Focus();
orders.Add("Cheese Burger");
}
else
{
txtCheeseBurger.Text = "0";
orders.Remove("Cheese Burger");
}
UpdateOrders();
}
private void UpdateOrders()
{
txtOrders.Text = string.Join(Environment.NewLine, orders);
}

The best way to do this is to have a routine that builds the contents of the text independent of what just happened -- this you could use join or a loop to create the text contents.
Make this a function and call it when the check boxes change. The function loops over all your items and adds them to the output with the formatting and totals etc.

Getting,reading,writing, and saving into one .txt file a collection of .txt documents contents. in visual c# using windows form

am new to c#,Here am trying to read multiple txt files with its contents at once, then using textbox to collect all the txt content, after collecting the content then I will save all the content back into once txt file. below is my code, pls help out.
Here is the interface of the app
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;
namespace FileSaver
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void panel2_Paint(object sender, PaintEventArgs e)
{
}
private void label1_Click(object sender, EventArgs e)
{
}
//File 004: Save the File in System Temporary path
private void button2_Click(object sender, EventArgs e)
{
if (txtFileContent.Visible == true)
{
SaveFile(Path.GetTempPath());
}
else
MessageBox.Show("This form saves only text files");
}
//File 001: Use File open dialog to get the file name
private void btn_File_Open_Click(object sender, EventArgs e)
{
List<String> MyStream = new List<string>();
string ext = "";
this.dlgFileOpen.Filter = "Text Files(*.txt) | *.txt";
this.dlgFileOpen.Multiselect = true;
if (dlgFileOpen.ShowDialog() == DialogResult.OK)
{
try
{
StringBuilder stbuilder = new StringBuilder();
foreach (var files in dlgFileOpen.SafeFileNames )
{
MyStream.Add(files + "\n");
Console.WriteLine();
}
foreach (var item in MyStream)
{
stbuilder.Append(item );
}
txtSelectedFile.Text = stbuilder.ToString() ;
ext = Path.GetExtension(dlgFileOpen.FileName);
}
catch (Exception ex)
{
MessageBox.Show("Error: Could not read file from disk. Original error: " + ex.Message);
}
if (ext == ".txt")
{
//003: The extension is txt. Read the file and display the content
txtFileContent.Visible = true;
FileStream filestream = new FileStream(dlgFileOpen.FileName, FileMode.Open);
StreamReader streamReader = new StreamReader(filestream);
while (streamReader.EndOfStream != true)
{
txtFileContent.AppendText(streamReader.ReadLine());
txtFileContent.AppendText(Environment.NewLine);
}
streamReader.Close();
}
}
}
private void txtSelectedFile_TextChanged(object sender, EventArgs e)
{
}
//File 002: Use the Path object to determine the selected file has the
// required extension.
private void dlgFileOpen_FileOk(object sender, CancelEventArgs e)
{
string Required_Ext = ".txt ";
string selected_ext = Path.GetExtension(dlgFileOpen.FileName);
int index = Required_Ext.IndexOf(selected_ext);
//002: Inform the user to select correct extension
if (index < 0)
{
MessageBox.Show("Extension Maaaan... Extension! Open only txt or bmp or jpg");
e.Cancel = true;
}
}
private void folderBrowserDialog1_HelpRequest(object sender, EventArgs e)
{
}
private void SaveFile_Click(object sender, EventArgs e)
{
//001: Setup the Folder dialog properties before the display
string selected_path = "";
dlgFolder.Description = "Select a Folder for Saving the text file";
dlgFolder.RootFolder = Environment.SpecialFolder.MyComputer;
//002: Display the dialog for folder selection
if (dlgFolder.ShowDialog() == DialogResult.OK)
{
selected_path = dlgFolder.SelectedPath;
if (string.IsNullOrEmpty(selected_path) == true)
{
MessageBox.Show("Unable to save. No Folder Selected.");
return;
}
}
//003: Perform the File saving operation. Make sure text file is displayed before saving.
if (txtFileContent.Visible == true)
{
SaveFile(selected_path);
}
else
MessageBox.Show("This form saves only text files");
}
public void SaveFile(string selected_path)
{
string Save_File;
if (selected_path.Length > 3)
Save_File = selected_path + "\\" + txtSaveFile.Text + ".txt";
else
Save_File = selected_path + txtSaveFile.Text + ".txt";
FileStream fstream = new FileStream(Save_File, FileMode.CreateNew);
StreamWriter writer = new StreamWriter(fstream);
writer.Write(txtFileContent.Text);
lblSavedLocation.Text = "Text File Saved in " + Save_File;
writer.Close();
}
private void txtSaveFile_TextChanged(object sender, EventArgs e)
{
}
}
}

Try this out. I stripped out all the the code i felt unnecessary for your problem:
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;
namespace FileSaver
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void panel2_Paint(object sender, PaintEventArgs e)
{
}
private void label1_Click(object sender, EventArgs e)
{
}
//File 004: Save the File in System Temporary path
private void button2_Click(object sender, EventArgs e)
{
if (txtFileContent.Visible == true)
{
SaveFile(Path.GetTempPath());
}
else
MessageBox.Show("This form saves only text files");
}
//File 001: Use File open dialog to get the file name
private void btn_File_Open_Click(object sender, EventArgs e)
{
this.dlgFileOpen.Filter = "Text Files(*.txt) | *.txt";
this.dlgFileOpen.Multiselect = true;
if (dlgFileOpen.ShowDialog() == DialogResult.OK)
{
var stBuilder = new StringBuilder();
foreach (var fileName in dlgFileOPen.FileNames)
{
stBuilder.AppendLine(File.ReadAllText(fileName));
}
txtFileContent.Text = stBuilder.ToString();
}
}
private void txtSelectedFile_TextChanged(object sender, EventArgs e)
{
}
//File 002: Use the Path object to determine the selected file has the
// required extension.
private void dlgFileOpen_FileOk(object sender, CancelEventArgs e)
{
}
private void folderBrowserDialog1_HelpRequest(object sender, EventArgs e)
{
}
private void SaveFile_Click(object sender, EventArgs e)
{
//001: Setup the Folder dialog properties before the display
string selected_path = "";
dlgFolder.Description = "Select a Folder for Saving the text file";
dlgFolder.RootFolder = Environment.SpecialFolder.MyComputer;
//002: Display the dialog for folder selection
if (dlgFolder.ShowDialog() == DialogResult.OK)
{
selected_path = dlgFolder.SelectedPath;
if (string.IsNullOrEmpty(selected_path) == true)
{
MessageBox.Show("Unable to save. No Folder Selected.");
return;
}
}
//003: Perform the File saving operation. Make sure text file is displayed before saving.
if (txtFileContent.Visible == true)
{
SaveFile(selected_path);
}
else
MessageBox.Show("This form saves only text files");
}
public void SaveFile(string selected_path)
{
string Save_File;
if (selected_path.Length > 3)
Save_File = selected_path + "\\" + txtSaveFile.Text + ".txt";
else
Save_File = selected_path + txtSaveFile.Text + ".txt";
File.WriteAllText(Save_File, txtFileContent.Text);
lblSavedLocation.Text = "Text File Saved in " + Save_File;
}
private void txtSaveFile_TextChanged(object sender, EventArgs e)
{
}
}
}

All looks good, except for the reading part, it can be done in a much easier way....
StringBuilder stbuilder = new StringBuilder();
foreach (var filePath in dlgFileOpen.FileNames)
{
StreamReader sr = new StreamReader(filePath);
stbuilder.Append(sr.ReadToEnd());
sr.Close();
//Or Much faster you can use
stbuilder.Append(File.ReadAllText(filePath));
stbuilder.Append(Environment.NewLine);
stbuilder.Append(Environment.NewLine);
txtFileContent.Text = stbuilder.ToString();
}

Reading and writing text files in C#

I am coding a program where I need to read, write, and filter data from one text file to a new one.
The main goal of this program is:
have the user select a text file with data that I have already created,
use a Substring to choose which characters to grab from the file,
write a file that matches the data from the text file.
I am a little stuck on getting the program to write files in general as well as grabbing certain characters from a text file.
If anyone could give me some pointers that would be awesome.
Thanks!
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.Diagnostics;
using System.IO;
namespace Project_4_osmvoe
{
public partial class Form1 : Form
{
string ham;
StreamReader pizza;
StreamWriter burger;
public Form1()
{
InitializeComponent();
}
private void button1_Click(object sender, EventArgs e)
{
DialogResult result = openFileDialog1.ShowDialog();
if (result == DialogResult.OK)
{
ham = openFileDialog1.FileName;
}
pizza = new StreamReader(ham);
lblInputFile.Text = ham;
}
private void button2_Click(object sender, EventArgs e)
{
DialogResult result = saveFileDialog1.ShowDialog();
if (result == DialogResult.OK)
{
ham = saveFileDialog1.FileName;
}
burger = new StreamWriter(ham);
lblOutputFile.Text = ham;
}
private void button3_Click(object sender, EventArgs e)
{
string line;
while ((line = pizza.ReadLine()) != null)
{
if (filter(line))
burger.WriteLine(line);
}
pizza.Close();
burger.Close();
MessageBox.Show("Output File Written");
}
private Boolean filter(string intext)
{
string gender = intext.Substring(0, 0);
string state = intext.Substring(0, 0);
if (((radioButtonFemale.Checked && gender.Equals("F")) ||
(RadioButtonMale.Checked && gender.Equals("M"))))
return true;
else
return false;
}
}
}

A part from the useful advices received in the comments above.
(Don't keep streams opened between events)
What do you think is the result of these lines?
string gender = intext.Substring(0, 0);
string state = intext.Substring(0, 0);
THe second parameter of Substring is the number of chars to extract from the string. Passing zero means that your returned string is empty, so the subsequent test is always false and you never write a line.
I suggest to store, in two different global variables, the names of the two files and, in button3_Click open the two streams
string inputFile;
string outputFile;
private void button1_Click(object sender, EventArgs e)
{
DialogResult result = openFileDialog1.ShowDialog();
if (result == DialogResult.OK)
{
inputFile = openFileDialog1.FileName;
lblInputFile.Text = inputFile;
}
}
private void button2_Click(object sender, EventArgs e)
{
DialogResult result = saveFileDialog1.ShowDialog();
if (result == DialogResult.OK)
{
outputFile = saveFileDialog1.FileName;
lblOutputFile.Text = outputFile ;
}
}
private void button3_Click(object sender, EventArgs e)
{
string line;
using(StreamReader pizza = new StreamReader(inputFile))
using(StreamWriter burger = new StreamWrite(outputFile))
{
while ((line = pizza.ReadLine()) != null)
{
if (!string.IsNullOrWhiteSpace(line) && filter(line))
burger.WriteLine(line);
}
}
MessageBox.Show("Output File Written");
}
private Boolean filter(string intext)
{
string gender = intext.Substring(0, 1);
string state = intext.Substring(0, 1);
if (((radioButtonFemale.Checked && gender.Equals("F")) ||
(RadioButtonMale.Checked && gender.Equals("M"))))
return true;
else
return false;
}

ADD url in textbox to listbox in Windows Form Application c#

Iam new in programming.In windows Form application ,I want user can write a url in textbox and add (with button) in listbox as a favorite list,then user can click in listbox and then go to browser, finaly can save and open the list? whitout Microsoft Sql Database.I Need a source code.
textbox: (Enter your WebSite) : www.google.com
Button:ADD To List Box
Listbox:WWW.Google.com
Button :Save
Button :Open

You have to save the ListBox.Items as plain text file if not wanting to use database. Without binding, this simple problem becomes a little nasty if you start digging into writing it. Here is one of the solution you may need:
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
int lastIndex = -1;
bool suppressSelectedIndexChanged;
//Click event handler for buttonAdd
private void buttonAdd_Click(object sender, EventArgs e)
{
listBox1.Items.Add(textBox1.Text);
suppressSelectedIndexChanged = true;
listBox1.SelectedIndex = listBox1.Items.Count - 1;
suppressSelectedIndexChanged = false;
}
//Click event handler for buttonRemove
private void buttonRemove_Click(object sender, EventArgs e)
{
if (listBox1.SelectedIndices.Count == 0) return;
int k = listBox1.SelectedIndices[0];
suppressSelectedIndexChanged = true;
for (int i = listBox1.SelectedIndices.Count - 1; i >= 0; i--)
listBox1.Items.RemoveAt(listBox1.SelectedIndices[i]);
suppressSelectedIndexChanged = false;
lastIndex = -1;
listBox1.SelectedIndex = k < listBox1.Items.Count ? k : listBox1.Items.Count - 1;
if (listBox1.Items.Count == 0) textBox1.Clear();
}
//Click event handler for buttonSave
private void buttonSave_Click(object sender, EventArgs e)
{
SaveFileDialog save = new SaveFileDialog();
save.Filter = "URLs file|*.urls";
save.FileOk += (s, ev) =>
{
using (StreamWriter writer = File.CreateText(save.FileName))
{
foreach (object item in listBox1.Items)
{
writer.WriteLine(item.ToString());
}
}
};
save.ShowDialog();
}
//Click event handler for buttonOpen
private void buttonOpen_Click(object sender, EventArgs e)
{
OpenFileDialog open = new OpenFileDialog();
open.Filter = "URLs file|*.urls";
open.FileOk += (s, ev) =>
{
listBox1.Items.Clear();
using (StreamReader reader = File.OpenText(open.FileName))
{
string line = "";
while ((line = reader.ReadLine()) != null)
{
listBox1.Items.Add(line);
}
}
};
open.ShowDialog();
}
//SelectedIndexChanged event handler for listBox1
private void listBox1_SelectedIndexChanged(object sender, EventArgs e)
{
if (suppressSelectedIndexChanged) return;
if (lastIndex > -1)
{
listBox1.Items[lastIndex] = textBox1.Text;
}
lastIndex = listBox1.SelectedIndex;
if (listBox1.SelectedIndex > -1)
textBox1.Text = listBox1.Items[listBox1.SelectedIndex].ToString();
}
//Click event handler for buttonVisit
private void buttonVisit_Click(object sender, EventArgs e)
{
if (listBox1.SelectedItem == null) return;
System.Diagnostics.Process.Start(listBox1.SelectedItem.ToString());
}
}
Here is the GUI screen shot for you to know which controls are needed:

private void btnAdd_Click(object sender, EventArgs e)
{
string _webstring = #"http://";
string _website = _webstring + textBox1.Text;
listBox1.Items.Add(_website);
using (StreamWriter w = File.AppendText("websites.txt"))
{
WriteLog(_website, w);
}
using (StreamReader r = File.OpenText("websites.txt"))
{
DisposeLog(r);
}
}
private void btnLaunch_Click(object sender, EventArgs e)
{
System.Diagnostics.Process.Start("iexplore.exe", listBox1.SelectedItem.ToString());
}
private void btnSave_Click(object sender, EventArgs e)
{
using (StreamWriter w = File.AppendText("websites.txt"))
{
foreach (string items in listBox1.Items)
{
WriteLog(items, w);
}
}
using (StreamReader r = File.OpenText("websites.txt"))
{
DisposeLog(r);
}
}
public static void WriteLog(string logMessage, TextWriter w)
{
w.WriteLine(logMessage, logMessage);
}
public static void DisposeLog(StreamReader r)
{
string line;
while ((line = r.ReadLine()) != null)
{
Console.WriteLine(line);
}
}
private void btnRetrieve_Click(object sender, EventArgs e)
{
using (TextReader txtRead = File.OpenText("Websites.txt"))
{
string _text = "";
string[] _textArray = null;
while ((_text = txtRead.ReadLine()) != null)
{
_textArray = _text.Split('\t');
listBox1.Items.Add(txtRead.ReadLine());
}
txtRead.Close();
}
}
hope this helps.. thanks

Deleting items from listbox raises exception

I need to be able to delete items from a listbox but when I press the delete function and say yes I want to delete I get this exception: Items collection cannot be modified when the DataSource property is set.
Now I want to know what to do about this.
namespace Flashloader
{
public partial class Form1 : Form
{
private controllerinifile _controllerIniFile;
private toepassinginifile _toepassingIniFile;
// private Toepassinglist _toepassingList;
private StringList _comPorts;
public Form1()
{
InitializeComponent();
backgroundWorker1.WorkerReportsProgress = true;
backgroundWorker1.WorkerSupportsCancellation = true;
button4.Visible = false;
_controllerIniFile = new controllerinifile();
_toepassingIniFile = new toepassinginifile(_controllerIniFile.Controllers);
// _toepassingList = new Toepassinglist(_controllerList).FromIniFile();
_comPorts = new StringList();
_applicationListBox.DataSource = _toepassingIniFile.ToePassingen;
_controllercombobox.DataSource = _controllerIniFile.Controllers;
_applicationListBox.Refresh();
_controllercombobox.Refresh();
Settings settings = _toepassingIniFile.Settings;
textBox3.Text = settings.Port;
textBox4.Text = settings.Baudrate;
}
// File select Button and file directory
private void button2_Click(object sender, EventArgs e)
{
appfile.Filter = "Srec Files (.a20; .a21; .a26; .a44)|*.a20; *.a21; *.a26; *.a44|All files (*.*)|*.*";
{
if (appfile.ShowDialog() == DialogResult.OK)
{
System.IO.StreamReader sr = new
System.IO.StreamReader(appfile.FileName);
sr.Close();
}
}
String filedata = appfile.FileName;
appfile.Title = ("Choose a file");
appfile.InitialDirectory = System.IO.Path.Combine(System.IO.Path.GetDirectoryName(Application.ExecutablePath), #"C:\\\\Projects\\flashloader2013\\mainapplication\\");
textBox1.Text = string.Format("{0}", appfile.FileName);
}
// textbox for the bootfile
private void textBox2_TextChanged(object sender, EventArgs e)
{
}
// start button for sending appfiles
private void button1_Click(object sender, EventArgs e)
{
backgroundWorker1.RunWorkerAsync();
serialPort1.Open();
if (MessageBox.Show(appfile.FileName + " is selected and ready to be send,Are you sure you want to send the selected file?", "", MessageBoxButtons.YesNo) == DialogResult.No)
{
MessageBox.Show("The selected file will not be send.", "", MessageBoxButtons.OK);
}
else
{
button1.Visible = false;
button4.Visible = true;
}
try
{
using (FileStream inputstream = new FileStream(OpenBoot.FileName, FileMode.Open, FileAccess.Read, FileShare.Read, 32 * 1024 * 1024, FileOptions.SequentialScan))
{
byte[] buffer = new byte[8 * 1024 * 1024];
long bytesRead = 0, streamLength = inputstream.Length;
inputstream.Position = 0;
while (bytesRead < streamLength)
{
long toRead = streamLength - bytesRead;
if (toRead < buffer.Length)
buffer = new byte[(int)toRead];
if (inputstream.Read(buffer, 0, buffer.Length) != buffer.Length)
throw new Exception("File read error");
bytesRead += buffer.Length;
serialPort1.Write(buffer, 0, buffer.Length);
}
}
}
catch
{
MessageBox.Show("No file selected");
}
StringList list = new StringList().FromFile(appfile.FileName);
// Read file and put it in a list that will be sorted.
foreach (String line in list)
{
list.Sort();
serialPort1.Write(line);
}
MessageBox.Show("Bootfile and Applicationfile are send succesfully.");
}
// abort button for sending files
private void button4_Click(object sender, EventArgs e)
{
backgroundWorker1.CancelAsync();
button4.Visible = false;
button1.Visible = true;
progressBar1.Value = 0;
timer1.Enabled = false;
serialPort1.Close();
}
// backgroundworkers
private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
{
DateTime start = DateTime.Now;
e.Result = "";
for (int i = 0; i < 100; i++)
{
System.Threading.Thread.Sleep(50);
backgroundWorker1.ReportProgress(i, DateTime.Now);
if (backgroundWorker1.CancellationPending)
{
e.Cancel = true;
return;
}
}
TimeSpan duration = DateTime.Now - start;
e.Result = "Duration: " + duration.TotalMilliseconds.ToString() + " ms.";
}
private void backgroundWorker1_ProgressChanged(object sender,
ProgressChangedEventArgs e)
{
progressBar1.Value = e.ProgressPercentage;
DateTime time = Convert.ToDateTime(e.UserState);
}
private void backgroundWorker1_RunWorkerCompleted(object sender,
RunWorkerCompletedEventArgs e)
{
if (e.Cancelled)
{
MessageBox.Show("The task has been cancelled");
}
else if (e.Error != null)
{
MessageBox.Show("Error. Details: " + (e.Error as Exception).ToString());
}
else
{
MessageBox.Show("The task has been completed. Results: " + e.Result.ToString());
}
}
private void Boot_button_Click(object sender, EventArgs e)
{
OpenBoot.Filter = "Binary Files (.BIN; .md6; .md7)|*.BIN; *.md6; *.md7|All Files (*.*)|*.*";
{
if (OpenBoot.ShowDialog() == DialogResult.OK)
{
System.IO.StreamReader sr = new
System.IO.StreamReader(appfile.FileName);
sr.Close();
}
}
String filedata = OpenBoot.FileName;
OpenBoot.Title = ("Choose a file");
OpenBoot.InitialDirectory = "C:\\Projects\\flashloader2013\\mainapplication\\Bootfiles";
textBox2.Text = string.Format("{0}", OpenBoot.FileName);
}
// Saving the settings to the INI file.
private void SaveSettings()
{
Toepassing toepassing = GetCurrentApplication();
if (toepassing == null)
{
MessageBox.Show("No Application selected");
return;
}
toepassing.Controller = (Controller)_controllercombobox.SelectedItem;
toepassing.Lastfile = textBox1.Text;
// toepassing.TabTip =
_toepassingIniFile.Save();
}
private Controller GetCurrentController()
{
int index = _controllercombobox.SelectedIndex;
if (index < 0)
return null;
return _controllerIniFile.Controllers[index];
}
private Toepassing GetCurrentApplication()
{
int index = _applicationListBox.SelectedIndex;
if (index < 0)
return null;
return _toepassingIniFile.ToePassingen[index];
}
private void typelistbox_SelectedIndexChanged(object sender, EventArgs e)
{
Toepassing toepassing = GetCurrentApplication();
if (toepassing == null)
{
// TODO velden leegmaken
}
else
{
// appfile.InitialDirectory = Path.GetDirectoryName(controller.Lastfile);
appfile.FileName = toepassing.Lastfile;
textBox1.Text = toepassing.Lastfile;
_controllercombobox.SelectedItem = toepassing.Controller;
}
}
private void _controllercombobox_SelectedIndexChanged(object sender, EventArgs e)
{
Controller controller = GetCurrentController();
if (controller == null)
{
// TODO velden leegmaken
}
else
{
textBox2.Text = controller.Bootfile;
}
}
private void exitToolStripMenuItem_Click(object sender, EventArgs e)
{
this.Close();
}
private void changeCurrentControllerToolStripMenuItem_Click(object sender, EventArgs e)
{
var controlleredit = new Controlleredit(_controllerIniFile);
controlleredit.Show();
Refresh();
}
private void addControllerToolStripMenuItem_Click(object sender, EventArgs e)
{
var controllersettings = new Newcontroller(_controllerIniFile);
controllersettings.ShowDialog();
_controllercombobox.DataSource = null;
_controllercombobox.DataSource = _controllerIniFile.Controllers;
// Refresh();
// _controllercombobox.Refresh();
}
private void newapplicationBtton_Click(object sender, EventArgs e)
{
var newapplication = new NewApplication(_toepassingIniFile);
newapplication.ShowDialog();
_applicationListBox.DataSource = null;
_applicationListBox.DataSource = _toepassingIniFile.ToePassingen;
}
/////////////////////////////The Error is down here /////////////////////////////
private void button3_Click(object sender, EventArgs e)
{
if (MessageBox.Show("You are about to delete application: "+ Environment.NewLine + _applicationListBox.SelectedItem +Environment.NewLine + " Are you sure you want to delete the application?", "", MessageBoxButtons.YesNo) == DialogResult.No)
{
MessageBox.Show("The application will not be deleted.", "", MessageBoxButtons.OK);
}
else if (this._applicationListBox.SelectedIndex >= 0)
this._applicationListBox.Items.RemoveAt(this._applicationListBox.SelectedIndex);
}
}
}

The error says it quite clearly: you have to remove the item from the underlying datasource, you can't delete it manually. If you want to remove/add items manually, you shouldn't use databinding but build the list by hand.

As exception say you can't delete items directly from ListBox - you have to remove it from underlying DataSource and then rebind control (if it is not bound to BindingSource for example)
private void button3_Click(object sender, EventArgs e)
{
if (MessageBox.Show("You are about to delete application: "+ Environment.NewLine + _applicationListBox.SelectedItem +Environment.NewLine + " Are you sure you want to delete the application?", "", MessageBoxButtons.YesNo) == DialogResult.No)
{
MessageBox.Show("The application will not be deleted.", "", MessageBoxButtons.OK);
}
else if (this._applicationListBox.SelectedIndex >= 0)
{
var item = this.GetCurrentApplication();
_toepassingIniFile.ToePassingen.Remove(item);
_applicationListBox.DataSource = null;
_applicationListBox.DataSource = _toepassingIniFile.ToePassingen;
}
}
Your code is hard to read so I was a bit guessing with classes etc, but it should work.

Try to remove from datasource itself as below:
string myobj = this._applicationListBox.SelectedValue.ToString();
data.Remove(myobj );
_applicationListBox.DataSource = null;
_applicationListBox.DataSource = data;

As others have said. You must have a list that is bound to the listbox. You cannot delete from the listbox directly.
You should delete from the List
private Toepassinglist _toepassingList
That is the datasource for your listbox.
Delete the item you want like so...
this._toepassingList.Items.RemoveAt(this._applicationListBox.SelectedIndex);

You can delete from list:---
ListName.Items.RemoveAt(postion);