如何：捕获异常
上次修改时间： 2010年3月24日
适用范围： SharePoint Server 2010
将可能引发异常的代码段放在 Try 块中，而将处理异常的代码放在 Catch 块中。Catch 语句的顺序很重要。发生异常时，异常沿堆栈向上传递，每个 Catch 块都有机会处理它。通过将异常类型与 Catch 块中指定的异常名称相匹配，可确定处理异常的 Catch 块。例如，以下 Catch 块将捕获简单对象访问协议 (SOAP) 异常：
catch (SoapException e)
{
Console.WriteLine("SOAP Exception Error Code: {0}",
e.SubCode.Code.Name);
Console.WriteLine("SOAP Exception Message is: {0}",
e.Message);
}
Catch e As SoapException
Console.WriteLine("SOAP Exception Error Code: {0}", e.SubCode.Code.Name)
Console.WriteLine("SOAP Exception Message is: {0}", e.Message)
End Try
如果不存在特定类型的 Catch 块，则由可能存在的常规 Catch 块来捕捉异常。例如，您可以通过添加以下代码来捕获一般异常：
catch (Exception e)
{
Console.WriteLine("Exception Message: {0}", e.Message);
}
Catch e As Exception
Console.WriteLine("Exception Message: {0}", e.Message)
End Try
将针对特定类型异常的 Catch 块放在一般异常之前。
公共语言运行库将捕捉 Catch 块未捕捉的异常。根据运行库的配置，可能会显示一个调试对话框，或者停止执行程序并显示一个包含异常信息的对话框。有关调试的详细信息，请参阅调试和分析应用程序（该链接可能指向英文页面）(https://msdn.microsoft.com/zh-cn/library/7fe0dd2y(vs.71).aspx)（该链接可能指向英文页面）。
有关如何处理异常的详细信息，请参阅异常处理的最佳做法（该链接可能指向英文页面） (https://msdn.microsoft.com/zh-cn/library/seyhszts(vs.71).aspx)（该链接可能指向英文页面）。
示例
using System;
using System.Text;
using System.Web.Services.Protocols;
using ExcelWebService.myserver02;
namespace ExcelWebService
{
class WebService
{
[STAThread]
static void Main(string[] args)
{
// Instantiate the Web service and make a status array object
ExcelService xlservice = new ExcelService();
Status[] outStatus;
RangeCoordinates rangeCoordinates = new RangeCoordinates();
string sheetName = "Sheet1";
// Set the path to the workbook to open.
// TODO: Change the path to the workbook
// to point to a workbook you have access to.
// The workbook must be in a trusted location.
// If workbookPath is a UNC path, the application
// must be on the same computer as the server.
// string targetWorkbookPath =
// @"\\MyServer\myxlfiles\Formulas.xlsx";
string targetWorkbookPath =
"http://myserver02/DocLib/Shared%20Documents/Basic1.xlsx";
// Set credentials for requests
xlservice.Credentials =
System.Net.CredentialCache.DefaultCredentials;
try
{
// Call the OpenWorkbook method and point to the
// trusted location of the workbook to open.
string sessionId = xlservice.OpenWorkbook(targetWorkbookPath, "en-US", "en-US", out outStatus);
Console.WriteLine("sessionID : {0}", sessionId);
// Prepare object to define range coordinates,
// and call the GetRange method.
rangeCoordinates.Column = 0;
rangeCoordinates.Row = 0;
rangeCoordinates.Height = 18;
rangeCoordinates.Width = 10;
object[] rangeResult1 = xlservice.GetRange(sessionId, sheetName, rangeCoordinates, false, out outStatus);
Console.WriteLine("Total rows in range: " + rangeResult1.Length);
Console.WriteLine("Sum in last column is: " + ((object[])rangeResult1[2])[3]);
// Close the workbook. This also closes the session.
xlservice.CloseWorkbook(sessionId);
}
catch (SoapException e)
{
Console.WriteLine("SOAP Exception Error Code: {0}",
e.SubCode.Code.Name);
Console.WriteLine("SOAP Exception Message is: {0}",
e.Message);
}
catch (Exception e)
{
Console.WriteLine("Exception Message: {0}", e.Message);
}
Console.ReadLine();
}
}
}
Imports System
Imports System.Text
Imports System.Web.Services.Protocols
Imports ExcelWebService.myserver02
Namespace ExcelWebService
Friend Class WebService
<STAThread> _
Shared Sub Main(ByVal args() As String)
' Instantiate the Web service and make a status array object
Dim xlservice As New ExcelService()
Dim outStatus() As Status
Dim rangeCoordinates As New RangeCoordinates()
Dim sheetName As String = "Sheet1"
' Set the path to the workbook to open.
' TODO: Change the path to the workbook
' to point to a workbook you have access to.
' The workbook must be in a trusted location.
' If workbookPath is a UNC path, the application
' must be on the same computer as the server.
' string targetWorkbookPath =
' @"\\MyServer\myxlfiles\Formulas.xlsx";
Dim targetWorkbookPath As String = "http://myserver02/DocLib/Shared%20Documents/Basic1.xlsx"
' Set credentials for requests
xlservice.Credentials = System.Net.CredentialCache.DefaultCredentials
Try
' Call the OpenWorkbook method and point to the
' trusted location of the workbook to open.
Dim sessionId As String = xlservice.OpenWorkbook(targetWorkbookPath, "en-US", "en-US", outStatus)
Console.WriteLine("sessionID : {0}", sessionId)
' Prepare object to define range coordinates,
' and call the GetRange method.
rangeCoordinates.Column = 0
rangeCoordinates.Row = 0
rangeCoordinates.Height = 18
rangeCoordinates.Width = 10
Dim rangeResult1() As Object = xlservice.GetRange(sessionId, sheetName, rangeCoordinates, False, outStatus)
Console.WriteLine("Total rows in range: " & rangeResult1.Length)
Console.WriteLine("Sum in last column is: " & (CType(rangeResult1(2), Object()))(3))
' Close the workbook. This also closes the session.
xlservice.CloseWorkbook(sessionId)
Catch e As SoapException
Console.WriteLine("SOAP Exception Error Code: {0}", e.SubCode.Code.Name)
Console.WriteLine("SOAP Exception Message is: {0}", e.Message)
Catch e As Exception
Console.WriteLine("Exception Message: {0}", e.Message)
End Try
Console.ReadLine()
End Sub
End Class
End Namespace
请参阅
任务
演练：使用 Excel Web Services 开发自定义应用程序