c＃索引超出了数组的范围

Question

Hello i'm getting "Index was outside the bounds of the array" if i'm putting value (i) in itemsWS.getItemInfo(itemLis[i].ToString())

    object[] itemDetails;
    object[] itemLis = itemsWS.searchItem("", "bread", "all");
    int xs = 35;
    int clefts = 0;

    for (int i = 0; i < itemLis.Length; i++)

    {
        itemDetails = itemsWS.getItemInfo(itemLis[i].ToString());
        Button myButtons = new Button();
        myButtons.Click += delegate
        {

            dataGridView1.ColumnCount = 11;

            dataGridView1.Columns[0].Name = "Item Code";
            dataGridView1.Columns[1].Name = "Description";
            dataGridView1.Columns[2].Name = "Sale Price";
            dataGridView1.Columns[3].Name = "Category";
            dataGridView1.Columns[4].Name = "Type";
            dataGridView1.Columns[5].Name = "Status";
            dataGridView1.Columns[6].Name = "Low Count";
            dataGridView1.Columns[7].Name = "Medium Count";
            dataGridView1.Columns[8].Name = "High Count";
            dataGridView1.Columns[9].Name = "Item Picture";
            dataGridView1.Columns[10].Name = "TEST";

            //here is where i'm getting error if i put i on the []

            itemDetail = itemsWS.getItemInfo(itemLi[i].ToString());

            //

            dataGridView1.Rows.Add(itemDetail);
            MessageBox.Show("data grid displayed!");

        };


        myButtons.Text = itemDetails[1].ToString() + "\n  " + itemDetails[2].ToString();
        myButtons.Top = cleft * 180;
        myButtons.Left = 70;
        myButtons.Location = new Point(xs, clefts);
        myButtons.Size = new Size(100, 60);
        tabPage1.Controls.Add(myButtons);
        xs += 135;

        if (xs >= 537)
        {
            xs = 35;
            clefts += 80;
        }

(this is the database)

The problem is if I replace [i] with [0]. It will only display the first value item in the database

(here is the GUI if i replaced [i] with [0]) Any button clicked would repeat the same output

Please any help would be greatly appreciated. I'm trying to display items from MySQL using new buttons which was generated that would be displayed on the datagridview. Thanks

Answer 1

Try storing the value of i in a local variable inside the delegate example:

myButtons.Click += delegate
{
  …
  int local_i = i;
  itemDetail = itemsWS.getItemInfo(itemLis[local_i].ToString());
  …
}

The value of i might be out of range by the time the delegate is actually executed.

Update: Without seeing all the other code in the application it is difficult to say for sure but it could be that itemLis does not contain the item at that index anymore by the time the delegate is executing.

Try using a foreach loop, this way you won't be retrieving the items from the itemLis array when the delegate is executing.

foreach (var item in itemLis)
{
 itemDetails = itemsWS.getItemInfo(item);
    ....
    myButtons.Click += delegate
         {
         ...
         itemDetail = itemsWS.getItemInfo(item);
         ...    
     }
  ...
}