问题
I'm having a hard time trying to get a Treeview to display child notes.
I have a DataTable which is filled with Data from a query.
The table is something like this.
| ParentOT | ChildOT
-------------------
1 | 2
1 | 3
1 | 4
4 | 5
5 | 6
now, what I need is to order this data in a TreeView.
The result must be something like this (using this same table)
1
|
--2
|
--3
|
--4
|
--5
|
--6
I tried to this on Windows Forms and the only thing I can get is the tree to show only 1 set of childs. like this
1
|
--2
|
--3
|
--4
|
--5
|
5
|
--6
I tried to do it like this:
DataTable arbolSub = mssql_cnn.ejecutarSqlSelect(q2);
//Metodo 2: muestra las ot correctamente pero no muestra mas detalle de subOT.
if (trvOTHs.Nodes.Count > 0)
{
trvOTHs.Nodes.Clear();
}
trvOTHs.BeginUpdate();
if (arb.Rows.Count > 0)
{
string otPadre = arb.Rows[0][0].ToString();
int nivel = 0;
trvOTHs.Nodes.Add(arbolSub.Rows[0]["OT Padre"].ToString());
for (int i = 0; i < arbolSub.Rows.Count; i++)
{
//trvOTHs.Nodes.Add(arbolSub.Rows[0]["OT Padre"].ToString());
if (arbolSub.Rows[i]["OT Padre"].ToString() == otPadre)
{
if (trvOTHs.Nodes[nivel].Text == otPadre)
{
trvOTHs.Nodes[nivel].Nodes.Add(arbolSub.Rows[i]["OT Hija"].ToString());
}
}
else
{
otPadre = arbolSub.Rows[i+1]["OT Padre"].ToString();
TreeNode nodo = new TreeNode(otPadre.ToString());
trvOTHs.Nodes.Add(nodo);
nivel++;
}
}
trvOTHs.Nodes[0].Remove();
trvOTHs.ExpandAll();
}
trvOTHs.EndUpdate();
where trvOTHs is a TreeView.
Please Help! Thanks
EDIT: Thanks for the reply. I finally worked around this,using a idea given by a friend and using something like the suggested solution by @Mohammad abumazen.
I ended up using two methods recursively:
private TreeView cargarOtPadres(TreeView trv, int otPadre, DataTable datos)
{
if (datos.Rows.Count > 0)
{
foreach (DataRow dr in datos.Select("OTPadre='"+ otPadre+"'"))
{
TreeNode nodoPadre = new TreeNode();
nodoPadre.Text = dr["OTPadre"].ToString();
trv.Nodes.Add(nodoPadre);
cargarSubOts(ref nodoPadre, int.Parse(dr["OTHija"].ToString()), datos);
}
}
return trv;
}
private void cargarSubOts(ref TreeNode nodoPadre, int otPadre, DataTable datos)
{
DataRow[] otHijas = datos.Select("OTPadre='" + otPadre +"'");
foreach (DataRow drow in otHijas)
{
TreeNode hija = new TreeNode();
hija.Text = drow["OTHija"].ToString();
nodoPadre.Nodes.Add(hija);
cargarSubOts(ref hija, int.Parse(drow["OTHija"].ToString()), datos);
}
}
This did it. I leave it here in case anyone needs it. Thanks again.
回答1:
The main issue in your code that you are not looking for the child parent in the tree view to add it under , you add them all under main parent.
i made some changes to your code hopefully it work straight forward or with minor changes at your side:
if (arb.Rows.Count > 0)
{
TreeNode MainNode = new TreeNode();
string otPadre = arb.Rows[0][0].ToString();
int nivel = 0;
MainNode.Text = otPadre;
trvOTHs.Nodes.Add(MainNode);
for (int i = 0; i < arbolSub.Rows.Count; i++)
{
TreeNode child = new TreeNode();
child.Text = row["OT Hija"].ToString();
if (arbolSub.Rows[i]["OT Padre"].ToString() == otPadre)
{
MainNode.Nodes.Add(child);
}
else
{
FindParent(MainNode, row["OT Padre"].ToString(), child);
}
}
trvOTHs.ExpandAll();
}
this function to find the parent node :
private void FindParent(TreeNode ParentNode, string Parent, TreeNode ChildNode)
{
foreach (TreeNode node in ParentNode.Nodes)
{
if (node.Text.ToString() == Parent)
{
node.Nodes.Add(ChildNode);
}
else
{
FindParent(node, Parent, ChildNode);
}
}
}
回答2:
I would do something like this, You should consider using Dictionary and HashSet for maximum performance:
//use this extension method for convenience
public static class TreeViewExtension {
public static void LoadFromDataTable(this TreeView tv, DataTable dt){
var parentNodes = dt.AsEnumerable()
.GroupBy(row => (string)row[0])
.ToDictionary(g=> g.Key, value=> value.Select(x=> (string)x[1]));
Stack<KeyValuePair<TreeNode,IEnumerable<string>>> lookIn = new Stack<KeyValuePair<TreeNode,IEnumerable<string>>>();
HashSet<string> removedKeys = new HashSet<string>();
foreach (var node in parentNodes) {
if (removedKeys.Contains(node.Key)) continue;
TreeNode tNode = new TreeNode(node.Key);
lookIn.Push(new KeyValuePair<TreeNode,IEnumerable<string>>(tNode,node.Value));
while (lookIn.Count > 0) {
var nodes = lookIn.Pop();
foreach (var n in nodes.Value) {
IEnumerable<string> children;
TreeNode childNode = new TreeNode(n);
nodes.Key.Nodes.Add(childNode);
if (parentNodes.TryGetValue(n, out children)) {
lookIn.Push(new KeyValuePair<TreeNode,IEnumerable<string>>(childNode,children));
removedKeys.Add(n);
}
}
}
tv.Nodes.Add(tNode);
}
}
}
//usage
treeView1.LoadFromDataTable(yourDataTable);
NOTE the input DataTable should contain data as you posted in your question. There is no need for other kinds of Sub-DataTable.
回答3:
Thanks for the reply. I finally worked around this,using a idea given by a friend and using something like the suggested solution by @Mohammad abumazen.
I ended up using two methods recursively:
private TreeView cargarOtPadres(TreeView trv, int otPadre, DataTable datos)
{
if (datos.Rows.Count > 0)
{
foreach (DataRow dr in datos.Select("OTPadre='"+ otPadre+"'"))
{
TreeNode nodoPadre = new TreeNode();
nodoPadre.Text = dr["OTPadre"].ToString();
trv.Nodes.Add(nodoPadre);
cargarSubOts(ref nodoPadre, int.Parse(dr["OTHija"].ToString()), datos);
}
}
return trv;
}
private void cargarSubOts(ref TreeNode nodoPadre, int otPadre, DataTable datos)
{
DataRow[] otHijas = datos.Select("OTPadre='" + otPadre +"'");
foreach (DataRow drow in otHijas)
{
TreeNode hija = new TreeNode();
hija.Text = drow["OTHija"].ToString();
nodoPadre.Nodes.Add(hija);
cargarSubOts(ref hija, int.Parse(drow["OTHija"].ToString()), datos);
}
}
This did it. I leave it here in case anyone needs it. Thanks again.
来源：https://stackoverflow.com/questions/19502975/adding-child-nodes-to-a-treeview-from-datatable-c-windows-forms