Treeview in web form check child nodes on parent node check

Question

Im using Treeview control of System.Web.UI class, to display Category and subcategory of an item.

I have tried the following code but no hope

        protected void tvwOrganisation_TreeNodeCheckChanged(object sender, TreeNodeEventArgs e)
        {
            if (tvwOrganisation.CheckedNodes.Count > 0)
            {
                // the selected nodes.
                foreach (TreeNode node in tvwOrganisation.CheckedNodes)
                {

                    if (node.ChildNodes.Count > 0)
                    {
                        foreach (TreeNode childNode in node.ChildNodes)
                        {
                            childNode.Checked = true;
                        }
                    }

                }

            }
}

Is there a way I can do this, I have tried javascript too.

Also what is the replace of AfterCheck - windows formd event in web forms.

Answer 1

The tree tag was as follows,

 <asp:TreeView ID="tvwRegionCountry" runat="server" ShowCheckBoxes="All" ExpandDepth="0"   AfterClientCheck="CheckChildNodes();" PopulateNodesFromClient="true" ShowLines="true" ShowExpandCollapse="true" OnTreeNodeCheckChanged="tvwRegionCountry_TreeNodeCheckChanged"
                                                    onclick="OnTreeClick(event)">
                                                </asp:TreeView>

Added following JS as mentioned in asp.net treeview checkbox selection

<script language="javascript" type="text/javascript">
    function OnTreeClick(evt) {
        var src = window.event != window.undefined ? window.event.srcElement : evt.target;
        var isChkBoxClick = (src.tagName.toLowerCase() == "input" && src.type == "checkbox");
        if (isChkBoxClick) {
            var parentTable = GetParentByTagName("table", src);
            var nxtSibling = parentTable.nextSibling;
            if (nxtSibling && nxtSibling.nodeType == 1)//check if nxt sibling is not null & is an element node
            {
                if (nxtSibling.tagName.toLowerCase() == "div") //if node has children
                {
                    //check or uncheck children at all levels
                    CheckUncheckChildren(parentTable.nextSibling, src.checked);
                }
            }
            //check or uncheck parents at all levels
            CheckUncheckParents(src, src.checked);
        }
    }

    function CheckUncheckChildren(childContainer, check) {
        var childChkBoxes = childContainer.getElementsByTagName("input");
        var childChkBoxCount = childChkBoxes.length;
        for (var i = 0; i < childChkBoxCount; i++) {
            childChkBoxes[i].checked = check;
        }
    }

    function CheckUncheckParents(srcChild, check) {
        var parentDiv = GetParentByTagName("div", srcChild);
        var parentNodeTable = parentDiv.previousSibling;

        if (parentNodeTable) {
            var checkUncheckSwitch;

            if (check) //checkbox checked
            {
                var isAllSiblingsChecked = AreAllSiblingsChecked(srcChild);
                if (isAllSiblingsChecked)
                    checkUncheckSwitch = true;
                else
                    return; //do not need to check parent if any(one or more) child not checked
            }
            else //checkbox unchecked
            {
                checkUncheckSwitch = false;
            }

            var inpElemsInParentTable = parentNodeTable.getElementsByTagName("input");
            if (inpElemsInParentTable.length > 0) {
                var parentNodeChkBox = inpElemsInParentTable[0];
                parentNodeChkBox.checked = checkUncheckSwitch;
                //do the same recursively
                CheckUncheckParents(parentNodeChkBox, checkUncheckSwitch);
            }
        }
    }

    function AreAllSiblingsChecked(chkBox) {
        var parentDiv = GetParentByTagName("div", chkBox);
        var childCount = parentDiv.childNodes.length;
        for (var i = 0; i < childCount; i++) {
            if (parentDiv.childNodes[i].nodeType == 1) //check if the child node is an element node
            {
                if (parentDiv.childNodes[i].tagName.toLowerCase() == "table") {
                    var prevChkBox = parentDiv.childNodes[i].getElementsByTagName("input")[0];
                    //if any of sibling nodes are not checked, return false
                    if (!prevChkBox.checked) {
                        return false;
                    }
                }
            }
        }
        return true;
    }

    //utility function to get the container of an element by tagname
    function GetParentByTagName(parentTagName, childElementObj) {
        var parent = childElementObj.parentNode;
        while (parent.tagName.toLowerCase() != parentTagName.toLowerCase()) {
            parent = parent.parentNode;
        }
        return parent;
    }

</script>

and it worked...