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POPopulate WinForms TreeView from DataTable
 

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    <p>I have a WinForm TreeView Control that displays the Parent Child relationship of CaseNotes(I know that means nothing to most of you but it helps me visualize the answers). </p> <p>I have a DataTable of the CaseNotes that I need to display. The Parent/Child is defined as: If the row has a ParentNoteID then it is a childNode of that note otherwise it is a rootNode. It could also be a parent note(but not a rootNode) if another row has it's ID as it's ParentNoteID.</p> <p>To complicate(maybe simplify) things I have the below working(mostly) code that colors the nodes alternatingly. I manually created a static collection for the treeview and it colors them fairly correctly. Now I need to dynamically populate the Nodes from my DataTable.</p> <p>Since I already am going thru the treeview node by node shouldn't I be able to append the data into this process somehow? Maybe I need to build the nodes first and then color as a separate routine but the Recursion Method would still apply, correct?</p> <p>Lets say I want to display CaseNoteID for each Node. That is returned in the DataTable and is unique.</p> <pre><code>foreach (TreeNode rootNode in tvwCaseNotes.Nodes) { ColorNodes(rootNode, Color.MediumVioletRed, Color.DodgerBlue); } protected void ColorNodes(TreeNode root, Color firstColor, Color secondColor) { root.ForeColor = root.Index % 2 == 0 ? firstColor : secondColor; foreach (TreeNode childNode in root.Nodes) { Color nextColor = childNode.ForeColor = childNode.Index % 2 == 0 ? firstColor : secondColor; if (childNode.Nodes.Count &gt; 0) { // alternate colors for the next node if (nextColor == firstColor) ColorNodes(childNode, secondColor, firstColor); else ColorNodes(childNode, firstColor, secondColor); } } } </code></pre> <h2>EDIT</h2> <p>My thoughts/attempts so far: </p> <pre><code> public void BuildSummaryView() { tvwCaseNotes.Nodes.Clear(); DataTable cNotesForTree = CurrentCaseNote.GetAllCNotes(Program._CurrentPerson.PersonID); foreach (var cNote in cNotesForTree.Rows) { tvwCaseNotes.Nodes.Add(new TreeNode("ContactDate")); } FormPaint(); } </code></pre> <p>Obviously this is flawed. One it just display's ContactDate over and over. Granted it shows it the correct number of times but I would like the Value of ContactDate(which is a Column in the database and is being returned in the DataTable. Second I need to add the ChildNode Logic. A <code>if (node.parentNode = node.CaseNoteID) blah...</code></p> <h2>EDIT 2</h2> <p>So I found this link, <a href="http://msdn.microsoft.com/en-us/library/system.windows.forms.treeview.beginupdate(VS.85).aspx" rel="noreferrer">here</a>, and it makes it seem like I need to get my DataTable into an ArrayList. Is that correct?</p> <h2>EDIT 3</h2> <p>Okay, thanks to Cerebus this is mostly working. I just have one more question. How do I take this--></p> <pre><code>DataTable cNotesForTree = CurrentCaseNote.GetAllCNotes(Program._CurrentPerson.PersonID); </code></pre> <p>and use my returned DataTable in this? Do I just replace this --></p> <pre><code> dt = new DataTable("CaseNotes"); dt.Columns.Add("NoteID", typeof(string)); dt.Columns.Add("NoteName", typeof(string)); DataColumn dc = new DataColumn("ParentNoteID", typeof(string)); dc.AllowDBNull = true; dt.Columns.Add(dc); // Add sample data. dt.Rows.Add(new string[] { "1", "One", null }); dt.Rows.Add(new string[] { "2", "Two", "1" }); dt.Rows.Add(new string[] { "3", "Three", "2" }); dt.Rows.Add(new string[] { "4", "Four", null }); dt.Rows.Add(new string[] { "5", "Five", "4" }); dt.Rows.Add(new string[] { "6", "Six", null }); dt.Rows.Add(new string[] { "7", "Seven", null }); dt.Rows.Add(new string[] { "8", "Eight", "7" }); dt.Rows.Add(new string[] { "9", "Nine", "8" }); </code></pre> <p>My confusion, I think, is do I still need to do the Column.Add and Row.Adds? Also how would the DataColumn translate to my real data structure? Sorry for the very ignorant questions, the good news is I never have to ask twice.</p> <h2>EDIT 4</h2> <p>The following is providing a runtime error. </p> <pre><code>if (nodeList.Find(FindNode) == null) { DataRow[] childRows = dt.Select("ParentNoteID = " + dr["NoteID"]); if (childRows.Length &gt; 0) { // Recursively call this function for all childRowsl TreeNode[] childNodes = RecurseRows(childRows); // Add all childnodes to this node. node.Nodes.AddRange(childNodes); } // Mark this noteID as dirty (already added). //doneNotes.Add(noteID); nodeList.Add(node); } </code></pre> <p>The error is as follows --> <strong><em>Cannot find column [ea8428e4]</em></strong> Which is the first 8 digits of the correct NoteID(I have to use a Guid). Should it be looking for a column of that name?? Because I am using a Guid is there something else I need to do? I changed all the references in mine and your code to Guid...</p>
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    1. CORegarding "Edit 2" - No, that is not necessary, as long as you can perform your own logic to manage iterations in the data structure.
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    2. CORegarding "Edit 3" - That part of my code was there to construct a sample table with sample data to make sure it works. If your GetAllCNotes function returns a DataTable with similar structure, then you can simply remove the entire CreateData function.
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    3. COThanks I was piecing that together. Thanks for everything! Question though. On this part --> DataRow[] childRows = dt.Select("ParentNoteID = " + dr["NoteID"]); It is giving me a runtime error as it cannot find a COLUMN by the name of but it then lists a value... Ideas?
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