C# Datalist delete specific row.

I'm currently developing a guestbook system, and I need admins to remove specific logs. The problem is I'm getting an error when trying to delete it.

The error is: Index was outside the range. It may not be negative and must be less than the crowd size. Parameter name: index

My code: asp.net

 <asp:DataList ID="guestBookDataList" runat="server" ondeletecommand="guestBookDataList_DeleteCommand">
    <ItemTemplate>
        <div id="guest-books">
            <span class="guestBook-Id"> # <%#DataBinder.Eval(Container.DataItem, "id") %></span><span class="guestBook-Name">Name: <%#DataBinder.Eval(Container.DataItem, "Name") %> </span>
            <span class="guestBook-Date"> Date: <%#DataBinder.Eval(Container.DataItem, "Date") %> </span> <br />
            <span class="guestBook-Text"> <%#DataBinder.Eval(Container.DataItem, "text") %> </span>
           <asp:LinkButton ID="LinkButtonDelete" CssClass="gastbok-remove" runat="server" CommandName="Delete">Delete<%#DataBinder.Eval(Container.DataItem, "id") %></asp:LinkButton>
        </div>                
    </ItemTemplate>
</asp:DataList>

My linkbutton is the delete button for each item in the datalist.

And my C# code that's giving me the error:

protected void guestBookDataList_DeleteCommand(
    object source, DataListCommandEventArgs e)
{
    int id = Convert.ToInt32(guestBookDataList.DataKeys[e.Item.ItemIndex]);
    db.deleteGeustBookLog(id); //calls the sql command
    bindList();
}

Basiclly I just need to retrive the guestbooklogs ID from the databse so I can delete it.

Been trying a lot of different methods and googling about this but I can't get it to work. So now I'm asking you. Thanks for your time.

Best Answer

Add a CommandArgument to the LinkButton with the ID of it. Then in the delete code, look for e.CommandArgument, and pass that value instead.

<asp:LinkButton id="LinkButton2" 
       Text="Delete"
       CommandName="Delete" 
       CommandArgument='<%#DataBinder.Eval(Container.DataItem, "id") %>' 
       OnCommand="DeleteGuestBookEntry" 
       Runat="server"/>

You could also give it a commandName like "DeleteGuestBookEntry" or something.

  void DeleteGuestBookEntry(Object sender, CommandEventArgs e) 
  {
     int id = Convert.ToInt32(e.CommandArgument);
     db.deleteGeustBookLog(id); //calls the sql command
     bindList();
  }

I'd always check to make sure that your ID is not null, and is numeric, etc, and add some error handling, but that's the down and dirty way to do it. :)

Related Solutions

C# – Cannot delete directory with Directory.Delete(path, true)

Editor's note: Although this answer contains some useful information, it is factually incorrect about the workings of Directory.Delete. Please read the comments for this answer, and other answers to this question.

I ran into this problem before.

The root of the problem is that this function does not delete files that are within the directory structure. So what you'll need to do is create a function that deletes all the files within the directory structure then all the directories before removing the directory itself. I know this goes against the second parameter but it's a much safer approach. In addition, you will probably want to remove READ-ONLY access attributes from the files right before you delete them. Otherwise that will raise an exception.

Just slap this code into your project.

public static void DeleteDirectory(string target_dir)
{
    string[] files = Directory.GetFiles(target_dir);
    string[] dirs = Directory.GetDirectories(target_dir);

    foreach (string file in files)
    {
        File.SetAttributes(file, FileAttributes.Normal);
        File.Delete(file);
    }

    foreach (string dir in dirs)
    {
        DeleteDirectory(dir);
    }

    Directory.Delete(target_dir, false);
}

Also, for me I personally add a restriction on areas of the machine that are allowed to be deleted because do you want someone to call this function on C:\WINDOWS (%WinDir%) or C:\.

C# – How to delete all files and folders in a directory

System.IO.DirectoryInfo di = new DirectoryInfo("YourPath");

foreach (FileInfo file in di.GetFiles())
{
    file.Delete(); 
}
foreach (DirectoryInfo dir in di.GetDirectories())
{
    dir.Delete(true); 
}

If your directory may have many files, EnumerateFiles() is more efficient than GetFiles(), because when you use EnumerateFiles() you can start enumerating it before the whole collection is returned, as opposed to GetFiles() where you need to load the entire collection in memory before begin to enumerate it. See this quote here:

Therefore, when you are working with many files and directories, EnumerateFiles() can be more efficient.

The same applies to EnumerateDirectories() and GetDirectories(). So the code would be:

foreach (FileInfo file in di.EnumerateFiles())
{
    file.Delete(); 
}
foreach (DirectoryInfo dir in di.EnumerateDirectories())
{
    dir.Delete(true); 
}

For the purpose of this question, there is really no reason to use GetFiles() and GetDirectories().

Best Answer

Related Solutions

C# – Cannot delete directory with Directory.Delete(path, true)

C# – How to delete all files and folders in a directory

Related Topic