使用 WCF 测试客户端在 Visual Studio 中运行 WCF 服务时出现 NullReferenceException

Question

我使用 WCF 类库模板创建了一个非常简单的项目，现在我正尝试在 Visual Studio 中运行它。 没有编译错误，但是当 WCF 测试客户端窗口打开时，我得到了一个带有异常的对话框，我无法理解发生了什么：

这里是异常的完整描述：

************** Exception Text **************
System.NullReferenceException: Object reference not set to an instance of an object.
   at Microsoft.Tools.Common.SdkPathUtility.GetRegistryValue(String registryPath, String registryValueName)
   at Microsoft.Tools.Common.SdkPathUtility.GetSdkPath(Version targetFrameworkVersion)
   at Microsoft.Tools.TestClient.ToolingEnvironment.get_MetadataTool()
   at Microsoft.Tools.TestClient.ServiceAnalyzer.GenerateProxyAndConfig(String projectPath, String address, String configPath, String proxyPath, Int32 startProgressPosition, Int32 endProgressPostition, BackgroundWorker addServiceWorker, String& errorMessage)
   at Microsoft.Tools.TestClient.ServiceAnalyzer.AnalyzeService(String address, BackgroundWorker addServiceWorker, Single startProgress, Single progressRange, String& errorMessage)
   at Microsoft.Tools.TestClient.Workspace.AddServiceProject(String endpoint, BackgroundWorker addServiceWorker, Single startProgress, Single progressRange, String& error)
   at Microsoft.Tools.TestClient.AddServiceExecutor.Execute(AddServiceInputs inputs, Workspace workspace, BackgroundWorker addServiceWorker)
   at Microsoft.Tools.TestClient.UI.MainForm.addServiceWorker_DoWork(Object sender, DoWorkEventArgs e)
   at System.ComponentModel.BackgroundWorker.OnDoWork(DoWorkEventArgs e)
   at System.ComponentModel.BackgroundWorker.WorkerThreadStart(Object argument)


************** Loaded Assemblies **************
mscorlib
    Assembly Version: 4.0.0.0
    Win32 Version: 4.0.30319.34209 built by: FX452RTMGDR
    CodeBase: file:///C:/Windows/Microsoft.NET/Framework/v4.0.30319/mscorlib.dll
----------------------------------------
WcfTestClient
    Assembly Version: 12.0.0.0
    Win32 Version: 12.0.21005.1 built by: REL
    CodeBase: file:///C:/Program%20Files%20(x86)/Microsoft%20Visual%20Studio%2012.0/Common7/IDE/WcfTestClient.exe
----------------------------------------
System
    Assembly Version: 4.0.0.0
    Win32 Version: 4.0.30319.34239 built by: FX452RTMGDR
    CodeBase: file:///C:/Windows/Microsoft.Net/assembly/GAC_MSIL/System/v4.0_4.0.0.0__b77a5c561934e089/System.dll
----------------------------------------
System.Windows.Forms
    Assembly Version: 4.0.0.0
    Win32 Version: 4.0.30319.34209 built by: FX452RTMGDR
    CodeBase: file:///C:/Windows/Microsoft.Net/assembly/GAC_MSIL/System.Windows.Forms/v4.0_4.0.0.0__b77a5c561934e089/System.Windows.Forms.dll
----------------------------------------
System.Drawing
    Assembly Version: 4.0.0.0
    Win32 Version: 4.0.30319.34209 built by: FX452RTMGDR
    CodeBase: file:///C:/Windows/Microsoft.Net/assembly/GAC_MSIL/System.Drawing/v4.0_4.0.0.0__b03f5f7f11d50a3a/System.Drawing.dll
----------------------------------------
System.Configuration
    Assembly Version: 4.0.0.0
    Win32 Version: 4.0.30319.34209 built by: FX452RTMGDR
    CodeBase: file:///C:/Windows/Microsoft.Net/assembly/GAC_MSIL/System.Configuration/v4.0_4.0.0.0__b03f5f7f11d50a3a/System.Configuration.dll
----------------------------------------
System.Xml
    Assembly Version: 4.0.0.0
    Win32 Version: 4.0.30319.34230 built by: FX452RTMGDR
    CodeBase: file:///C:/Windows/Microsoft.Net/assembly/GAC_MSIL/System.Xml/v4.0_4.0.0.0__b77a5c561934e089/System.Xml.dll
----------------------------------------
System.ServiceModel
    Assembly Version: 4.0.0.0
    Win32 Version: 4.0.30319.34230 built by: FX452RTMGDR
    CodeBase: file:///C:/Windows/Microsoft.Net/assembly/GAC_MSIL/System.ServiceModel/v4.0_4.0.0.0__b77a5c561934e089/System.ServiceModel.dll
----------------------------------------
System.Core
    Assembly Version: 4.0.0.0
    Win32 Version: 4.0.30319.34209 built by: FX452RTMGDR
    CodeBase: file:///C:/Windows/Microsoft.Net/assembly/GAC_MSIL/System.Core/v4.0_4.0.0.0__b77a5c561934e089/System.Core.dll
----------------------------------------

我的项目中只有两个文件，IProductService：

namespace LayerNorthwindService
{
    // NOTE: You can use the "Rename" command on the "Refactor" menu to change the interface name "IService1" in both code and config file together.
    [ServiceContract]
    public interface IProductService
    {
        [OperationContract]
        Product GetProduct(int id);

        [OperationContract]
        bool UpdateProduct(Product product, ref string message);

        // TODO: Add your service operations here
    }

    // Use a data contract as illustrated in the sample below to add composite types to service operations.
    // You can add XSD files into the project. After building the project, you can directly use the data types defined there, with the namespace "LayerNorthwindService.ContractType".
    [DataContract]
    public class Product
    {
        [DataMember]
        public int ProductID { get; set; }
        [DataMember]
        public string ProductName { get; set; }
        [DataMember]
        public string QuantityPerUnit { get; set; }
        [DataMember]
        public decimal UnitPrice { get; set; }
        [DataMember]
        public bool Discontinued { get; set; }
    }
}

和产品服务：

namespace LayerNorthwindService
{
    // NOTE: You can use the "Rename" command on the "Refactor" menu to change the class name "Service1" in both code and config file together.
    public class ProductService : IProductService
    {
        public Product GetProduct(int id)
        {
            var product = new Product();
            product.ProductID = id;
            product.ProductName = "Product name";
            product.UnitPrice = 10.0m;
            product.QuantityPerUnit = "fake QPU";
            return product;
        }

        public bool UpdateProduct(Product product, ref string message)
        {
            var result = true;

            if (product.UnitPrice <= 0)
            {
                message = "Prince cannot be <= 0";
                result = false;
            }
            else if (string.IsNullOrEmpty(product.ProductName))
            {
                message = "product name cannot be empty";
                result = false;
            }
            else if (string.IsNullOrEmpty(product.QuantityPerUnit))
            {
                message = "QPU cannot be empty";
                result = false;
            }
            else
            {
                message = "product updated successfully";
                result = true;
            }

            return result;
        }
    }
}

Answer 1

在尝试从注册表读取信息时，“WCF 测试客户端”中似乎存在错误。

如果查看源代码，则实际上可以不安装 SDK。但是这个错误阻止了该工具实际使用在访问注册表失败时运行的代码，因为 NullReferenceException 不是预期的，但它应该是。在不存在的键上调用 OpenSubKey 会返回 null，因此在通过 GetValue 访问时会失败。

// Microsoft.Tools.Common.SdkPathUtility
private static string GetRegistryValue(string registryPath, string registryValueName)
{
    string result;
    try
    {
        using (RegistryKey registryKey = RegistryKey.OpenBaseKey(RegistryHive.LocalMachine, RegistryView.Registry32))
        {
            using (RegistryKey registryKey2 = registryKey.OpenSubKey(registryPath, false))
            {
                string text = registryKey2.GetValue(registryValueName, string.Empty) as string;
                result = text;
            }
        }
    }
    catch (UnauthorizedAccessException)
    {
        result = string.Empty;
    }
    catch (SecurityException)
    {
        result = string.Empty;
    }
    return result;
}

那么应该如何向微软报告呢？

Answer 2

我解决了我的问题，按照这个问题的公认答案：Unable to add service in WcfTestClient when copy to a different machine

由于我使用的是 Windows 8.1，我已经安装了适用于 Windows 8.1 的 Windows SDK，现在一切正常。

如果您要在您的机器上安装它，请注意您要安装的 SDK 的版本。每个 Windows 版本都有一个正确的版本。