Wcf 用户代码未处理toList()System.InvalidCastException
我已经使用LINQtoSQL(使用以下代码)编写了一个WCF服务。在对同一数据库调用同一服务的wcf函数后,调用对象的.ToList()方法时,我面临无效强制转换异常 例外情况是:Wcf 用户代码未处理toList()System.InvalidCastException,wcf,linq-to-sql,windows-services,.net,appdata,Wcf,Linq To Sql,Windows Services,.net,Appdata,我已经使用LINQtoSQL(使用以下代码)编写了一个WCF服务。在对同一数据库调用同一服务的wcf函数后,调用对象的.ToList()方法时,我面临无效强制转换异常 例外情况是: System.InvalidCastException was unhandled by user code Message=Specified cast is not valid. Source=System.Data StackTrace: at System.Data.SqlClien
System.InvalidCastException was unhandled by user code
Message=Specified cast is not valid.
Source=System.Data
StackTrace:
at System.Data.SqlClient.SqlBuffer.get_Int64()
at System.Data.SqlClient.SqlDataReader.GetInt64(Int32 i)
at Read_Command(ObjectMaterializer`1 )
at System.Data.Linq.SqlClient.ObjectReaderCompiler.ObjectReader`2.MoveNext()
at System.Collections.Generic.List`1..ctor(IEnumerable`1 collection)
at System.Linq.Enumerable.ToList[TSource](IEnumerable`1 source)
at SystemsManager.ACS.GetCommands(Int64 agentId) in E:\Projects\SystemsManager\AgentControlService\ACS.svc.cs:line 167
at SyncInvokeGetCommands(Object , Object[] , Object[] )
at System.ServiceModel.Dispatcher.SyncMethodInvoker.Invoke(Object instance, Object[] inputs, Object[]& outputs)
at System.ServiceModel.Dispatcher.DispatchOperationRuntime.InvokeBegin(MessageRpc& rpc)
InnerException:
我遇到的具体问题是ToList()方法
以下是wcf服务接口中的命令模型
[DataContract]
[Table(Name = "Command")]
public class Command
{
[DataMember, Column(IsPrimaryKey = true, Name = "Command_Id", AutoSync = AutoSync.OnInsert, IsDbGenerated = true, DbType = "Bigint NOT null identity")]
public long CommandId { get; set; }
[DataMember, Column(Name = "Agent_Id")]
public long AgentId { get; set; }
[DataMember, Column(Name = "Name")]
public string CommandName { get; set; }
[DataMember, Column(Name = "Paramters")]
public string CommandParamters { get; set; }
[DataMember, Column(Name = "Is_Fetched")]
public bool IsFectched { get; set; }
[DataMember, Column(Name = "Status")]
public long Status { get; set; }
[DataMember, Column(Name = "Response")]
public string Response { get; set; }
[DataMember, Column(Name = "Created")]
public DateTime Created { get; set; }
[DataMember, Column(Name = "Last_Modified")]
public DateTime LastModified { get; set; }
[DataMember, Column(Name = "Is_Enabled")]
public bool IsEnabled { get; set; }
}
重要的是:我的数据库文件位于WCF服务的AppData文件夹中。在我的wcf服务中,我只使用了一个db对象的实例(参考上面的第一个代码块),我想知道这是否是问题的原因
此外,我还从桌面应用程序调用了两个类似的方法来实现这个非常相同的wcf服务,但我没有遇到任何这样的问题
请帮忙。如果需要更多详细信息,请说明。。唯一可以想到的是,数据库可能正在使用中,当服务与数据库建立另一个连接时,它会失败。并使用“快速观察”>“重新评估”按钮重试几次,在观察窗口中显示所需的值,而不会引发任何错误
请帮我做这件事。高度赞赏快速响应
谢谢
史蒂夫别管男人了。我解决了 对于获得无效强制转换异常的任何其他人,以下是解决方案。 只有当实际的类模型与数据库不同时,才会发生错误 如果通过手工编码创建了类模型,则必须将表的每个列名与相应的类相匹配LINQ to sql在无法将数据库类型转换为.Net类型并引发无效强制转换异常时遇到错误。 因此,在大多数情况下,手动修复模型类中的错误或重新生成类都可以解决问题
var agent = client.GetAgentByIpAddress(myIPAddress);
client.Close();
if (agent != null)
{
if (agent.AgentId != -1)
{
client = new ACSClient();
var command = client.GetCommands(agent.AgentId);
.....
[DataContract]
[Table(Name = "Command")]
public class Command
{
[DataMember, Column(IsPrimaryKey = true, Name = "Command_Id", AutoSync = AutoSync.OnInsert, IsDbGenerated = true, DbType = "Bigint NOT null identity")]
public long CommandId { get; set; }
[DataMember, Column(Name = "Agent_Id")]
public long AgentId { get; set; }
[DataMember, Column(Name = "Name")]
public string CommandName { get; set; }
[DataMember, Column(Name = "Paramters")]
public string CommandParamters { get; set; }
[DataMember, Column(Name = "Is_Fetched")]
public bool IsFectched { get; set; }
[DataMember, Column(Name = "Status")]
public long Status { get; set; }
[DataMember, Column(Name = "Response")]
public string Response { get; set; }
[DataMember, Column(Name = "Created")]
public DateTime Created { get; set; }
[DataMember, Column(Name = "Last_Modified")]
public DateTime LastModified { get; set; }
[DataMember, Column(Name = "Is_Enabled")]
public bool IsEnabled { get; set; }
}