Disabling Controls in Node

1 posts, 0 answers
  1. Brad
    Brad avatar
    3 posts
    Member since:
    Mar 2011

    Posted 09 Mar 2011 Link to this post

    I'm adding  nodes to the treeview at page load. Also at the same time I am adding a Label and a DropDown control to the node.

    I want to disable the DropDowns for certain nodes  based on what node was checked. The Error I'm getting is :
    "Object reference not set to an instance of an object."

    This is because the the TreeView1.Nodes(0).Nodes(i).Count is 0. But it shouldn't be.

    Does anyone know what I'm doing wrong here?


    Heres how I am creating the nodes:
                For i As Integer = 0 To DsStateDistrictID.Tables(0).Rows.Count - 1
                    Dim treeNode As New Telerik.Web.UI.RadTreeNode(DsStateDistrictID.Tables(0).Rows(i).Item("DistrictName").ToString)
                    treeNode.Value = DsStateDistrictID.Tables(0).Rows(i).Item("StateDistrictID").ToString
                    treeNode.Checkable = True

                    'Add Label with StateDistrict Name to Node
                    Dim lbl As Label = New Label
                    lbl.Text = DsStateDistrictID.Tables(0).Rows(i).Item("DistrictName").ToString
                    lbl.ID = "lbl" & DsStateDistrictID.Tables(0).Rows(i).Item("StateDistrictID").ToString.Trim
                    treeNode.Controls.Add(lbl)

                    'Add Color DropDown to Node
                    Dim ddColor As DropDownList = New DropDownList
                    ddColor.ID = "dd" '& DsStateDistrictID.Tables(0).Rows(i).Item("StateDistrictID").ToString.Trim
                    ddColor = BuildColorDropDown(ddColor)
                    treeNode.Controls.Add(ddColor)
                    TreeView1.Nodes(0).Nodes.Add(treeNode)


                Next


            End If


    Heres how I am trying to disable the drop down list:
    For i As Integer = 0 To TreeView1.Nodes(0).Nodes.Count - 1
                        Dim StateDistrictID As String = TreeView1.Nodes(0).Nodes(i).Value.ToString.Trim
                        Dim ddColor As New DropDownList
                        ddColor = CType(TreeView1.Nodes(0).Nodes(i).FindControl("dd" & StateDistrictID), DropDownList)
                        ddColor.Enabled = False
    Next
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