ASP.NET Cannot create ActiveX component

Question

I have a ASP.NET application that allows users to export their staff's absences each month to Microsoft Excel. The application is currently generating the following exception

Exception: Cannot create ActiveX component.

with the following stack trace

System.Exception: Cannot create ActiveX component. at Microsoft.VisualBasic.Interaction.CreateObject(String ProgId, String ServerName) at HR.ManagerSummary.ExportToExcel() in H:\Development\pagec\Visual Studio 2005\Projects\HR\ysnet2\Time\ManagerSummary.aspx.vb:line 935 at HR.ManagerSummary.btnExcel_Click(Object sender, EventArgs e) in H:\Development\pagec\Visual Studio 2005\Projects\HR\ysnet2\Time\ManagerSummary.aspx.vb:line 891 at System.Web.UI.WebControls.Button.OnClick(EventArgs e) at System.Web.UI.WebControls.Button.RaisePostBackEvent(String eventArgument) at System.Web.UI.WebControls.Button.System.Web.UI.IPostBackEventHandler.RaisePostBackEvent(String eventArgument) at System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler sourceControl, String eventArgument) at System.Web.UI.Page.RaisePostBackEvent(NameValueCollection postData) at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)

The code fails at the CreateObject line.

    'Create the Excel object
    Dim objXL As Object = CreateObject("Excel.Application") ' New Microsoft.Office.Interop.Excel.Application
    Dim objWB As Object = objXL.Workbooks.Add
    Dim objWS As Object = objWB.Worksheets(1)

I've set permission in DCOM Config for Microsoft Excel Application for the IUSR_ account but that has not resolved the issue. Any ideas would greatly be appreciated.

Cheers

James

Answer 1

Following migration of our ASP.NET applications to new hardware, I investigated this issue further and came up with a solution.

To resolve the issue, open "Component Services" from Administrative Tools and navigate as follows:

• Component Services -> Computers -> My Computer -> DCOM Config -> Microsoft Excel Application
• Right click Microsoft Excel Application -> Properties -> Security tab
• Click Customize for "Launch and Activation Permissions" -> Edit -> Add
• Enter "NETWORK SERVICE", click "Check Names", click OK
• Allow "Local Launch" and "Local Activation" for "NETWORK SERVICE" then click OK
• Select Customize for "Access Permissions" -> Edit -> Add
• Enter "NETWORK SERVICE", click "Check Names", click OK
• Allow "Local Access" for for "NETWORK SERVICE" then click OK
• Click OK

The ASP.NET application can now successfully create a Microsoft Excel worksheet containing the exported data.