Elton's Ark : C# Programming

Got an error today: EventType clr20r3, P1...

Elton — Mon, 06 Mar 2006 11:24:00 GMT

Today after I compiled my winform program in Windows XP with .NET Framework 2.0, I copied the assembly to another Windows 2003 ENT Server. When I run this program in W2k3 server, nothing responded, and following message is created in Application Events....(read more)

Sort the objects in ArrayList

Elton — Tue, 21 Feb 2006 21:51:00 GMT

It should be a frequent scenario to sort the order of objects in a collection, such as ArrayList. ArrayList in c# provide a method named Sort(). But we need to let ArrayList know the detailed sorting algorithm.

There are two means to implement this:

1. Make the target class inheritted from IComparable interface, and provide CompareTo() method. IComparable interface comes from System namespace.

For example:

    class UITestCase: IComparable
    {
        private int _sequenceno = 0;
        public int SequenceNo
        {
            get
            {
                return _sequenceno;
            }
            set
            {
                _sequenceno = value;
            }
        }
......

        // implement the IComparable interface, define the algorithm here
        public Int32 CompareTo(object next)
        {
            UITestCase nextCase = (UITestCase)next;

            return (this.SequenceNo.CompareTo(nextCase.SequenceNo));
        }
    } // class end.

When using ArrayList to store a group of UITestCase objects, we could simply call ArrayList.Sort() to sort all objects in it.

                // get all test case entities, then make sort order
                ArrayList caseList = new ArrayList();
                foreach (DirectoryInfo dir in nodeDirInfo.GetDirectories("*.tc"))
                {
                    UITestCase testcase = new UITestCase(dir.FullName);

caseList.Add(testcase);
}

                if (caseList.Count > 0)
                {
                    caseList.Sort();
                }

2. Create a class inherited from IComparer interface, then implement Compare(object x, object y) method just like IComparable's CompareTo(object next) method.

3. Write a special method to sort the order of a given ArrayList like what we will do in C language, I prefer this one because I think the codes writing in above two methods are not straightforward enough.

the LabelEdit property in TreeView class

Elton — Fri, 20 Jan 2006 19:35:00 GMT

Today I want to add the RENAME feature to maintain the Test Case Tree in StepRecorder, which exactly like the operation in Windows Explorer. After user right click a node, the selected node turns to Edit Mode, and user could type the new name in the edit box. System will ask user to reinput the new name if some invalid characters are entered such as "!"/","/"@"... and the selected node will remain in its Edit Mode for user's re-input.

To carry out this function, TreeView.LabelEdit property, TreeNode.BeginEdit() and TreeNode.EndEdit(bool) will be used as well as the TreeView.AfterLabelEdit event.

Here is a demo code from MSDN and I think it greatly show how these property/method/event work together.

/* Get the tree node under the mouse pointer and
   save it in the mySelectedNode variable. */
private void treeView1_MouseDown(object sender,
System.Windows.Forms.MouseEventArgs e)
{
   mySelectedNode = treeView1.GetNodeAt(e.X, e.Y);
}

private void menuItem1_Click(object sender, System.EventArgs e)
{
   if (mySelectedNode != null && mySelectedNode.Parent != null)
   {
      treeView1.SelectedNode = mySelectedNode;
      treeView1.LabelEdit = true;
      if(!mySelectedNode.IsEditing)
      {
         mySelectedNode.BeginEdit();
      }
   }
   else
   {
      MessageBox.Show("No tree node selected or selected node is a root node.\n" +
         "Editing of root nodes is not allowed.", "Invalid selection");
   }
}

private void treeView1_AfterLabelEdit(object sender,
         System.Windows.Forms.NodeLabelEditEventArgs e)
{
   if (e.Label != null)
   {
     if(e.Label.Length > 0)
     {
        if (e.Label.IndexOfAny(new char[]{'@', '.', ',', '!'}) == -1)
        {
           // Stop editing without canceling the label change.
           e.Node.EndEdit(false);
        }
        else
        {
           /* Cancel the label edit action, inform the user, and
              place the node in edit mode again. */
           e.CancelEdit = true;
           MessageBox.Show("Invalid tree node label.\n" +
              "The invalid characters are: '@','.', ',', '!'",
              "Node Label Edit");
           e.Node.BeginEdit();
        }
     }
     else
     {
        /* Cancel the label edit action, inform the user, and
           place the node in edit mode again. */
        e.CancelEdit = true;
        MessageBox.Show("Invalid tree node label.\nThe label cannot be blank",
           "Node Label Edit");
        e.Node.BeginEdit();
     }
     this.treeView1.LabelEdit = false;
   }
}

How to drag and drop the treenode in TreeView Controls

Elton — Fri, 16 Dec 2005 05:57:00 GMT

Found a great article on this, and I will investigate it latter.

http://www.codeproject.com/cs/miscctrl/TreeViewDragDrop.asp