[英]How to assign variable from different tables?
我有一個資產制造商和型號表的列表。 我需要使用 AssetMakeString 分配 Asset Make。 目前我有:
public class FuelLightTruckDataSource
{
public Model.Asset Asset { get; set; }
public Employee Employee { get; set; }
public FuelProductClass ProductClass { get; set; }
public FuelVendor Vendor { get; set; }
public FuelFillSource FillSource { get; set; }
public AssetModel Model { get; set; }
public AssetMake Make { get; set; }
public string Source { get; set; }
public string City { get; set; }
public decimal Volume { get; set; }
public decimal? Distance { get; set; }
public decimal? Odomoter { get; set; }
public decimal? DistanceVolume { get; set; }
public float? ConsumptionRate { get; set; }
public DateTime? Date { get; set; }
public decimal? ConsumptionCalculated { get; set; }
public decimal? DistanceCalculated { get; set; }
public FuelLightTruckDataSource() { }
public static List<FuelLightTruckDataSource> Get(DateTime from, DateTime to)
{
List<FuelLightTruckDataSource> data = new List<FuelLightTruckDataSource>();
using (SystemContext ctx = new SystemContext())
{
List<FuelLightTruckDataSource> dataTransactions
= ctx.FuelTransaction
.Where(tx => DbFunctions.TruncateTime(tx.DateTime) >= from.Date && DbFunctions.TruncateTime(tx.DateTime) <= to.Date
//&& tx.AssetFilled.AssignedToEmployee.Manager
&& tx.AssetFilled.AssignedToEmployee != null
//&
&& tx.AssetFilled.AssetType.Code == "L"
&& (tx.FuelProductType.FuelProductClass.Code == "GAS" || tx.FuelProductType.FuelProductClass.Code == "DSL"))
.GroupBy(tx => new { tx.AssetFilled, tx.DateTime, tx.FuelProductType.FuelProductClass, tx.FuelCard.FuelVendor, tx.City, tx.Volume, tx.Odometer}) //Added tx.volume to have individual transactions
.Select(g => new FuelLightTruckDataSource()
{
Asset = g.FirstOrDefault().AssetFilled,
Model = g.FirstOrDefault().AssetFilled.AssetModel,
Make = g.FirstOrDefault().AssetFilled.AssetModel.AssetMakeString,
Employee = g.FirstOrDefault().AssetFilled.AssignedToEmployee,
ProductClass = g.FirstOrDefault().FuelProductType.FuelProductClass,
Vendor = g.FirstOrDefault().FuelCard.FuelVendor,
FillSource = FuelFillSource.Transaction,
Source = "Fuel Station",
City = g.FirstOrDefault().City.ToUpper(),
Volume = g.FirstOrDefault().Volume,
Distance = g.FirstOrDefault().Odometer,
Date = g.FirstOrDefault().DateTime
})
// .OrderBy(tx => tx.Date)
.ToList();
我的 AssetModel 類如下所示:
{
public class AssetModel
{
public int Id { get; set; }
[Required]
[MaxLength(100)]
[Index("IX_AssetModel", 2, IsUnique = true)]
public string Name { get; set; }
[MaxLength(10)]
[Index("IX_AssetModel", 3, IsUnique = true)]
public string Year { get; set; }
public string Description { get; set; }
[Index("IX_AssetModel", 1, IsUnique = true)]
public int? AssetMakeId { get; set; }
public virtual AssetMake AssetMake { get; set; }
public virtual List<Asset> Assets { get; set; }
// **** Custom Properties ****
public string AssetMakeName { get { return AssetMake.Name; } }
public string AssetMakeString { get { return AssetMake.Name + " " + Name + (Year == null ? "" : " (" + Year + ")"); } }
}
}
為什么我收到“錯誤:無法將類型‘字符串’隱式轉換為‘PSI.ManagementSystem.Model.AssetMake’”?
FuelLightTruckDataSource.Make
聲明如下:
public AssetMake Make { get; set; }
Make
的類型是AssetMake
。 您不能為其分配字符串。 您必須為其分配AssetMake
。
相反,您在此處為其分配一個字符串,編譯器不會接受它,因為它無法將字符串隱式轉換為AssetMake
:
Make = g.FirstOrDefault().AssetFilled.AssetModel.AssetMakeString
AssetMakeString
是一個字符串。 它是這樣聲明的:
public string AssetMakeString { get {
return AssetMake.Name + " " + Name
+ (Year == null ? "" : " (" + Year + ")"); } }
所以你不能使用該字符串來初始化FuelLightTruckDataSource.Make
。 與其將您從數據庫中獲取的資產 make 轉換為字符串,然后將其分配給您無法將其分配給的內容,您想要做的只是分配資產 make 本身。
您認為您可以找到AssetModel
類型的AssetMake
嗎? 如果您閱讀AssetModel
的類定義,您可能會找到一個。 如果你能找到一個,那可能是你想要使用的屬性而不是AssetMakeString
。
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