CODEWITHSUNDEEP
c#asp.nettreeview
Mike
Mike

Reputation: 1067

Why Treeview doesn't show the hierarchy?

I have added a treeview to my system. I could manage to show the content of the treeview. But the output is not same as I expected. Here I have added an image of the output. Please take look at it.

aspx code 

<asp:TreeView ID="TreeView1" runat="server" ImageSet="XPFileExplorer"
                         NodeIndent="15">
     <HoverNodeStyle Font-Underline="True" ForeColor="#6666AA" />
     <NodeStyle Font-Names="Tahoma" Font-Size="8pt" ForeColor="Black" HorizontalPadding="2px"
              NodeSpacing="0px" VerticalPadding="10px"></NodeStyle>
     <ParentNodeStyle Font-Bold="False" />
     <SelectedNodeStyle BackColor="#B5B5B5" Font-Underline="False" HorizontalPadding="0px"
              VerticalPadding="2px" />
</asp:TreeView>

C# code

protected void Page_Load(object sender, EventArgs e)
{
    if (!IsPostBack)
    {
        dt=getDataObj.treeSketch();
        PopulateTreeView(dt, 0, null);
    }
}       

private void PopulateTreeView(DataTable dsParent, int parentId, TreeNode treeNode)
{
     foreach (DataRow row in dsParent.Rows)
     {
          TreeNode child = new TreeNode
          {
                Text = row["FUNCTION_NAME"].ToString(),
                Value = row["FUNCTION_CODE"].ToString()
          };
          if (parentId == 0)
          {
                TreeView1.Nodes.Add(child);
                dt = getDataObj.loadTree(child);
                PopulateTreeView(dt, int.Parse(child.Value), child);
          }
          else
          {
                treeNode.ChildNodes.Add(child);
          }
     }
 }

TreeView image
In here nodes in capital letters are main node and other are child nodes. Why doesn't it appear like a treeview? How to make it work?

Query 

public DataTable loadTree(TreeNode child)
{
     string strQuery = @"select FUNCTION_CODE,USER_TYPE from [WEB_FUNCTIONACCESS]
                        where FUNCTION_CODE = '"+ child +"' ";

    return SqlHelper.ExecuteDataset(strConnStringAppeal, CommandType.Text, strQuery).Tables[0];
}

Upvotes: 0

Views: 316

Answers (1)

woodykiddy
woodykiddy

Reputation: 6455

The problem is actually pretty obvious. 

if (parentId == 0)
      {
            TreeView1.Nodes.Add(child);
            dt = getDataObj.loadTree(child);
            PopulateTreeView(dt, int.Parse(child.Value), child);
      }
      else
      {
            treeNode.ChildNodes.Add(child);
      }

So the condition is that if parentId is 0 then add a root level node, otherwise add at the child level.

Now when you call this method, PopulateTreeView(dt, 0, null), the parentId parameter is always 0.

Update:

I see you have a recursive call to the method, PopulateTreeView, given the child value. int.Parse(child.Value) does this always evaluate as 0?

The problem is you used the reference of child which gives you a TreeNode object. What you really should be using is child.Value which gives you a string value. Then you can append it to the query string there.

Upvotes: 1

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