ThreadAbortException

March 2006 Entries

ASP.NET Webservices "The test form is only available for requests from the local machine"

ASP.NET Webservices have reduced the complexity involved in developing web services, thanks to tools like Visual Studio .NET, Visual Studio 2005 which reduce the over head of manually creating the proxy files and schema.

We can invoke a service by browsing the <ServiceName>.asmx file and trying to invoke the webmethods available, from the local machine.

However, the webservice is a scenario where, usually the service lies on a different machine other than the machine where the application which consumes the service, resides.

If we would like to invoke the service from other machine, by default, it would display the message "The test form is only available for requests from the local machine."

To enable the Service to be invoked from remote machine, we need to add the following settings to the Web.Config file of the Web Service Application.


<system.web>
<webServices>
<protocols>
<add name="HttpGet"/>
<add name="HttpPost"/>
</protocols>
</webServices>
</system.web>

This would enable the Web service to be able to be invoked from remote machine. However, this invoking would work only for simple data types and would not work in the case of complex datatypes.

Similarly, this setting would only be useful in development / testing scenarios and it is advisable to remove / comment the above section when releasing for production, due to security reasons.

This articles applies to both .NET 1.1 as well as .NET 2.0.

Cheers and Happy Web Servicing !!!

ASP.NET 2.0 Treeview Checkboxes - Check All - Javascript

An update to this post is available at http://geekswithblogs.net/ranganh/archive/2009/01/21/updated-asp.net-treeview-checkboxes-ndash-check-all-ndash-javascript.aspx with suggestions from the comments below and it works when I last checked in IE 8 Beta2, Firefox 3.0.5 and Safari 3.2.1

ASP.NET 2.0 has introduced many new promising controls and TreeView is one among them. There has always been a requirement for Tree Control in earlier versions and it was quite hard to manage them with either the third party controls or the lighter version - IE Webcontrols.

Thanks to ASP.NET team, the 2.0 version rolled out with a built-in Treeview Control. The TreeView has many built-in features such as showing a checkbox for all the Tree Nodes. Node level formating, style, etc., Enabling the ShowCheckBoxes="All" property sets it to show a checkbox for all the nodes. The other options are Leaf, None, Parent and Root which show checkboxes at the respective node levels. None doesnt display CheckBoxes.

When we set ShowCheckBoxes="All", we would like to provide a feature where people can select the checkbox on the Root Node so that all the other checkboxes are checked automatically. Basically, when the parent node is checked, all the child nodes should be checked automatically.

It would be intuitive to accomplish this task at the client side without involving a postback.

The following code snippet helps in accomplishing the same.

TreeView Declaration

<asp:TreeView ID="TreeView1" Runat="server" DataSourceID="XmlDataSource1" onclick="client_OnTreeNodeChecked();" ShowCheckBoxes="all">

<DataBindings>

<asp:TreeNodeBinding DataMember="Category" ValueField="ID" TextField="Name"></asp:TreeNodeBinding>

<asp:TreeNodeBinding DataMember="Description" ValueField="Value" TextField="Value"></asp:TreeNodeBinding>

</DataBindings>

</asp:TreeView>


In the above TreeView declaration Code, you can find the property onclick="client_OnTreeNodeChecked();" event which actually is the JavaScript function which would accomplish this task.

The Javascript Code snippet is as follows:-

<script language="javascript" type="text/javascript">
function client_OnTreeNodeChecked()
{
var obj = window.event.srcElement;
var treeNodeFound = false;
var checkedState;
if (obj.tagName == "INPUT" && obj.type == "checkbox") {
var treeNode = obj;
checkedState = treeNode.checked;
do
{
obj = obj.parentElement;
} while (obj.tagName != "TABLE")
var parentTreeLevel = obj.rows[0].cells.length;
var parentTreeNode = obj.rows[0].cells[0];
var tables = obj.parentElement.getElementsByTagName("TABLE");
var numTables = tables.length
if (numTables >= 1)
{
for (i=0; i < numTables; i++)
{
if (tables[i] == obj)
{
treeNodeFound = true;
i++;
if (i == numTables)
{
return;
}
}
if (treeNodeFound == true)
{
var childTreeLevel = tables[i].rows[0].cells.length;
if (childTreeLevel > parentTreeLevel)
{
var cell = tables[i].rows[0].cells[childTreeLevel - 1];
var inputs = cell.getElementsByTagName("INPUT");
inputs[0].checked = checkedState;
}
else
{
return;
}
}
}
}
}
}
</script>

You may find that in Visual Studio 2005 the onclick method declared in the TreeView is underlined as an error, but still it would work.

This is a simple but sometimes frustrating requirement and hope this benefits similar requirements.

Thanks to
mtntime77 for posting the original idea.

A relevant article on XML Data binding with Treeview with checked state

Cheers and Happy TreeViewing.