C# System.InvalidOperationException：从具体化的“System.Int32”类型到可为空的“Country”类型的指定转换无效
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System.InvalidOperationException: The specified cast from a materialized 'System.Int32' type to a nullable 'Country' type is not valid
提问by Paul McLean
I have a particular unit test that runs fine on my personal PC, but whenever I get TFS to run the test, it fails with the following exception -
我有一个特定的单元测试在我的个人 PC 上运行良好，但是每当我让 TFS 运行测试时，它都会失败并出现以下异常 -
System.InvalidOperationException: The specified cast from a materialized 'System.Int32' type to a nullable 'Country' type is not valid.
System.InvalidOperationException：从具体化的“System.Int32”类型到可为空的“Country”类型的指定转换无效。
By following the stack trace, it has a problem with the following method -
通过跟踪堆栈跟踪，以下方法存在问题 -
public IEnumerable<IAddress> AddressSelectAll(long userID)
{
using (var context = new Entities())
{
var addresses = context.Customers
.Where(x => x.UserId == userID)
.Select(y => new Address
{
Address1 = y.Address1,
Address2 = y.Address2,
Address3 = y.Address3,
AddressID = y.AddressId,
City = y.City,
Country = y.Country != null ? (Country)y.Country : (Country?)null,
Postcode = y.Postcode,
State = y.State,
RecordEntryDate = y.RecordEntryDate,
Type = (AddressType)EFFunctions.ConvertToInt32(y.AddressType),
UserID = y.UserId
}).ToList();
return addresses.ToList();
}
}
In case it's relevant (doubt it is), my EFFunctions class is defined as -
如果它是相关的（怀疑是），我的 EFFunctions 类被定义为 -
public static class EFFunctions
{
[EdmFunction("Model", "ConvertToInt32")]
public static int ConvertToInt32(string text)
{
var result = string.IsNullOrEmpty(text) ? 0 : Convert.ToInt32(text);
return result;
}
}
And my .edmx has the following in it -
我的 .edmx 中有以下内容 -
<Function Name="ConvertToInt32" ReturnType="Edm.Int32">
<Parameter Name="v" Type="Edm.String" />
<DefiningExpression>
CAST(v AS Edm.Int32)
</DefiningExpression>
</Function>
Is anyone able to tell me what I'm doing wrong?
有没有人能告诉我我做错了什么？
采纳答案by Steve Westbrook
Your problem is probably with the line (or part of line)
您的问题可能与线路（或线路的一部分）有关
Country = y.Country != null ? (Country)y.Country : (Country?)null
You cast the value to Country in one case and Country? in another. Perhaps you could replace the value with -1, or, probably more reliably, change the Customer.Country type to Country? instead of Country.
您在一种情况下将值转换为 Country 和 Country？在另一个。也许您可以用 -1 替换该值，或者更可靠地将 Customer.Country 类型更改为 Country？而不是国家。
