So this is a really stupid problem, When I load up the same CSV file multiple times into my program this results in a messagebox appearing multiple times (n). The times I've opened a file. I'll post some code here to hopefully see why this is happening.

   public partial class Form1 : Form
   {
       [DllImport("shlwapi.dll")]
       public static extern int ColorHLSToRGB(int H, int L, int S);
       public
           bool First = true;
       
       public Form1()
       {
           InitializeComponent();

       }
public void button1_Click(object sender, EventArgs e) #button1 is used to start OpenFileDialog
       {
 OpenFileDialog openFileDialog1 = new OpenFileDialog
           {
               InitialDirectory = @"D:\",
               Title = "Browse Text Files",

               CheckFileExists = true,
               CheckPathExists = true,

               DefaultExt = "csv",
               Filter = "csv files (*.csv)|*.csv",
               FilterIndex = 2,
               RestoreDirectory = true,

               ReadOnlyChecked = true,
               ShowReadOnly = true
           };

           if (openFileDialog1.ShowDialog() == DialogResult.OK)
           {
               textBox1.Text = openFileDialog1.FileName;
               PickCount.Clear();
               PickCountProduct.Clear();
               PickCountSchap.Clear();
               LocatieProduct.Clear();
           }


              
               foreach (Control c in Controls) #I have ~400 clickable textboxes which display extra information when clicked. Therefore I store them
               {
                   if (c is TextBox)
                   {
                       textBoxes.Add(c);
                   }
                }

                   foreach (var c in textBoxes)
                   { c.Click  = textbox_Click;
}
}
public void textbox_Click(object sender, EventArgs e)
       {
           string location = ((TextBox)sender).Text;
           int pickcount = 0;
           string product = "";
           bool Test3 = PickCountSchap.TryGetValue(location, out int test);
           if (Test3)
           {
               pickcount = test;
           }
           else pickcount = 0;
           bool Test2 = LocatieProduct.TryGetValue(location, out HashSet<string> test2);
           if (Test2)
           {
               foreach (var output in test2)
               {

                   int i = output.IndexOf(" ")   1;
                   string str = output.Substring(i);
                 //  Console.WriteLine(str);
                   bool Test4 = PickCountProduct.TryGetValue(str, out int test3);
                   if (Test4 == false)
                   {
                    product = product   "\n"   output   " PickCount: onbekend";
                       
                   }
               
                   else product = product   "\n"   output   " PickCount: "   PickCountProduct[str];
               }
           }
           else product = "Geen informatie over producten op deze locatie gevonden";
           if (First)
           {
               MessageBox.Show("Informatie over schap "   location   "\nPickCount: "   pickcount   "\nProducten op deze locatie: "   product);
             
           }
           

       }

So I have a button1, which opens a file explorer, from which I choose a .csv file. When I load in multiple files in a row I get the MessageBox from clicking a textbox the amount of times I've loaded in a file. I can't find out why this is happening, so I hope one of you has had this issue before or can see in my code why it is happening.

Kind regards, DKT

CodePudding user response：

With each button1_Click you add another event handler to the Click event of the text boxes. So when button1_Click is executed twice, each click on the text box will invoke textbox_Click twice etc.

The solution is to remember if you already added the event handlers and skip this step the second time.