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How to: Handle Exceptions Thrown by a Web Service Method

  • Article

This topic is specific to a legacy technology. XML Web services and XML Web service clients should now be created using Windows Communication Foundation.

The following code example of a client calling a Web service method catches a SoapException thrown by the Web service method. The client then populates an HTML table with the properties of the caught SoapException.For more on handling SOAP faults received by Web service clients, see Handling and Throwing Exceptions in XML Web Services.

Example

<%@ Import Namespace="System.Web.Services.Protocols" %>
<%@ Import Namespace="System.Xml" %>
<%@ Page Language="vb" %>
<html>
 <head>
 <script runat=server language=vb>
    Sub Page_Load(o As Object, e As EventArgs)
       ' Create a new instance of the Web service class.
       Dim ThrowsSoapException As ThrowSoapException = New _
                 ThrowSoapException()
       Try
         ThrowsSoapException.myThrow()
       Catch myerr As SoapException
            ' Populate the table with the exception details.
            ErrorTable.Rows.Add(BuildNewRow("Fault Code Namespace", _
                                myerr.Code.Namespace))
            ErrorTable.Rows.Add(BuildNewRow("Fault Code Name", _
                                myerr.Code.Name))
            ErrorTable.Rows.Add(BuildNewRow( _
              "SOAP Actor that threw Exception", myerr.Actor))
            ErrorTable.Rows.Add(BuildNewRow("Error Message", _
                                 myerr.Message))
            ErrorTable.Rows.Add(BuildNewRow("Detail", _
                HttpUtility.HtmlEncode(myerr.Detail.OuterXml) )) 
            Return
        End Try
    End Sub 'Page_Load
     
    Function BuildNewRow(Cell1Text As String, Cell2Text As String) _
             As HtmlTableRow
        Dim row As New HtmlTableRow()
        Dim cell1 As New HtmlTableCell()
        Dim cell2 As New HtmlTableCell()
        
        'Set the contents of the two cells.
        cell1.Controls.Add(New LiteralControl(Cell1Text))
        'Add the cells to the row.
        row.Cells.Add(cell1)
        
        cell2.Controls.Add(New LiteralControl(Cell2Text))
        
        'Add the cells to the row.
        row.Cells.Add(cell2)
        Return row
    End Function 'BuildNewRow 
 </script>
 <head>
 <body>
     <table id="ErrorTable" CellPadding=5 CellSpacing=0 Border="1" BorderColor="black" runat="server" />
 </body>

<%@ Import Namespace="System.Web.Services.Protocols" %>
<%@ Import Namespace="System.Xml" %>
<%@ Page Language="C#" %>
<html>
 <head>
 <script runat=server language=c#>
 void Page_Load(Object o, EventArgs e){
 
   // Create a new instance of the Web service proxy class.
   ThrowSoapException throwSoapException = new ThrowSoapException();

   // Make a call to the Web service method, which throws an
   // exception.
    try
    {
       throwSoapException.myThrow();
    }
    catch (SoapException error) 
    {
       // Populate the table with the exception details.
       ErrorTable.Rows.Add(BuildNewRow("Fault Code Namespace",
                                        error.Code.Namespace));
       ErrorTable.Rows.Add(BuildNewRow("Fault Code Name",
                                        error.Code.Name)); 
       ErrorTable.Rows.Add(BuildNewRow(
          "SOAP Actor that threw Exception", error.Actor));
       ErrorTable.Rows.Add(BuildNewRow("Error Message",
           error.Message));
       ErrorTable.Rows.Add(BuildNewRow("Detail",
           HttpUtility.HtmlEncode(error.Detail.OuterXml)));

       return;
     }
 
 }
// This populates a row in an HtmlTable.
 HtmlTableRow BuildNewRow(string Cell1Text, string Cell2Text) {
     HtmlTableRow row = new HtmlTableRow();
     HtmlTableCell cell1 = new HtmlTableCell();
     HtmlTableCell cell2 = new HtmlTableCell();
     
     //Set the contents of the two cells.
     cell1.Controls.Add(new LiteralControl(Cell1Text));
     //Add a cell to the row.
     row.Cells.Add(cell1);
 
     cell2.Controls.Add(new LiteralControl(Cell2Text));
 
     //Add a cell to the row.
     row.Cells.Add(cell2);
     return row;
     
 }
 </script>
 <head>
 <body>
     <table id="ErrorTable" CellPadding=5 CellSpacing=0 Border="1" BorderColor="black" runat="server" />
 </body>

See Also

Tasks

How to: Throw Exceptions from a Web Service Created Using ASP.NET

Reference

SoapException Class
SoapHeaderException Class

Concepts

Handling and Throwing Exceptions in XML Web Services
Building XML Web Service Clients

Other Resources

Handling and Throwing Exceptions
XML Web Services Using ASP.NET