Nullreference exception

This is a discussion on Nullreference exception within the C# Programming forums, part of the General Programming Boards category; hi all i have errors while bulding the code in c# Code: private void subMenuModify_Click(object sender, System.EventArgs e) { int ...

  1. #1
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    Question Nullreference exception

    hi all

    i have errors while bulding the code in c#

    Code:
     private void subMenuModify_Click(object sender, System.EventArgs e)
            {
                int nStart = X;
                int spos = 0;
                int epos = this.lvFiles.Columns[0].Width;
                for (int i = 0; i < this.lvFiles.Columns.Count; i++)
                {
                    if (nStart > spos && nStart < epos)
                    {
                        subItemSelected = i;
                        break;
                    }
    
                    spos = epos;
                    epos += this.lvFiles.Columns[i].Width;
                }
                subItemText = this.lvItem.SubItems[2].Text;
    the line at which exception occurs is subItemText = this.lvItem.SubItems[2].Text;

    the exception is as follows:


    Nullreference exception was unhandled

    Object reference not set to an instance of an object.


    Pls anyone help me resolve this issue?

  2. #2
    Registered User valaris's Avatar
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    Looks like that item doesn't exist in your menu. Make sure there are at least 3 items in your menu or that will not work.

  3. #3
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    Question

    which item do you think is missing here? u mean "modify item"?

  4. #4
    Registered User valaris's Avatar
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    Code:
    subItemText = this.lvItem.SubItems[2].Text;
    This indexer tries to access something that doesn't exist probably. Make sure you have 3 items at least in this collection. It's usually not good to address menu's in this order unless you are guaranteed to have something there, otherwise you can get exceptions like this.

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