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我使用ADO.NET over Entity Framework來獲得高性能，因爲我的應用程序的數據複雜度有點高。因此，有混淆以下兩種方法：將數據錶轉換爲列表<T>（模型類列表）通用方法性能
方法1 - 通用方法對於所有
我使用下面的泛型方法對數據錶轉換成相應的模型對象。在這裏它使用反射並匹配模型的所有屬性和地圖的數據表頭，並構建適當的列表。
#region ConvertToList
/// <summary>
/// DataTableToList --- This function is used to Convert DataTable to List
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
public static List<T> DataTableToList<T>(DataTable dtDataCollection) where T : new()
{
var objList = new List<T>();
//Define what attributes to be read from the class
const BindingFlags flags = BindingFlags.Public | BindingFlags.Instance;
//Read Attribute Names and Types
var objFieldNames = typeof(T).GetProperties(flags).Cast<PropertyInfo>().
Select(item => new
{
Name = item.Name.ToLower(),
Type = Nullable.GetUnderlyingType(item.PropertyType) ?? item.PropertyType
}).ToList();
//Read Datatable column names and types
var dtlFieldNames = dtDataCollection.Columns.Cast<DataColumn>().
Select(item => new
{
Name = item.ColumnName.ToLower(),
Type = item.DataType
}).ToList();
foreach (DataRow dataRow in dtDataCollection.AsEnumerable().ToList())
{
var classObj = new T();
foreach (var dtField in dtlFieldNames)
{
PropertyInfo propertyInfos = classObj.GetType().GetProperty(dtField.Name, BindingFlags.IgnoreCase | BindingFlags.Public | BindingFlags.Instance);
var field = objFieldNames.Find(x => x.Name == dtField.Name);
if (field != null)
{
if (propertyInfos.PropertyType == typeof(DateTime))
{
propertyInfos.SetValue
(classObj, convertToDateTime(dataRow[dtField.Name]), null);
}
else if (propertyInfos.PropertyType == typeof(int))
{
propertyInfos.SetValue
(classObj, ConvertToInt(dataRow[dtField.Name]), null);
}
else if (propertyInfos.PropertyType == typeof(long))
{
propertyInfos.SetValue
(classObj, ConvertToLong(dataRow[dtField.Name]), null);
}
else if (propertyInfos.PropertyType == typeof(decimal))
{
propertyInfos.SetValue
(classObj, ConvertToDecimal(dataRow[dtField.Name]), null);
}
else if (propertyInfos.PropertyType == typeof(Boolean))
{
propertyInfos.SetValue
(classObj, ConvertToBool(dataRow[dtField.Name]), null);
}
else if (propertyInfos.PropertyType == typeof(String))
{
if (dataRow[dtField.Name].GetType() == typeof(DateTime))
{
propertyInfos.SetValue
(classObj, ConvertToDateString(dataRow[dtField.Name]), null);
}
else
{
propertyInfos.SetValue
(classObj, ConvertToString(dataRow[dtField.Name]), null);
}
}
}
}
objList.Add(classObj);
}
return objList;
}
/// <summary>
/// ConvertToDateString --- This function is used to convert object to DateString
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private static string ConvertToDateString(object dtValue)
{
if (dtValue == null && dtValue == DBNull.Value)
return string.Empty;
//return SpecialDateTime.ConvertDate(Convert.ToDateTime(date));
return Convert.ToString(dtValue);
}
/// <summary>
/// ConvertToString --- This function is used to convert object to string
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private static string ConvertToString(object strValue)
{
// return Convert.ToString(HelperFunctions.ReturnEmptyIfNull(value));
string returnValue = string.Empty;
if (strValue != null && strValue != DBNull.Value)
returnValue = Convert.ToString(strValue);
return returnValue;
}
/// <summary>
/// ConvertToInt --- This function is used to convert object to Int
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private static int ConvertToInt(object iValue)
{
//return Convert.ToInt32(HelperFunctions.ReturnZeroIfNull(value));
int returnValue = 0;
if (iValue != null && iValue != DBNull.Value)
returnValue = Convert.ToInt32(iValue);
return returnValue;
}
/// <summary>
/// ConvertToLong ---This function is used to convert object to Long
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private static long ConvertToLong(object lngValue)
{
//return Convert.ToInt64(HelperFunctions.ReturnZeroIfNull(value));
Int64 returnValue = 0;
if (lngValue != null && lngValue != DBNull.Value)
returnValue = Convert.ToInt64(lngValue);
return returnValue;
}
/// <summary>
/// ConvertToDecimal --- This function is used to convert object to Decimal
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private static decimal ConvertToDecimal(object decValue)
{
//return Convert.ToDecimal(HelperFunctions.ReturnZeroIfNull(value));
decimal returnValue = 0;
if (decValue != null && decValue != DBNull.Value)
returnValue = Convert.ToDecimal(decValue);
return returnValue;
}
/// <summary>
/// DateTime --- This function is used to convert object to convertToDateTime
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private static DateTime? convertToDateTime(object dtValue)
{
// return Convert.ToDateTime(HelperFunctions.ReturnDateTimeMinIfNull(date));
DateTime? returnValue = null;
if (dtValue != null && dtValue != DBNull.Value)
returnValue = Convert.ToDateTime(dtValue);
return returnValue;
}
/// <summary>
/// ConvertToBool ---This function is used to convert object to Bool
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private static bool ConvertToBool(object blValue)
{
//return Convert.ToDecimal(HelperFunctions.ReturnZeroIfNull(value));
bool returnValue = false;
if (blValue != null && blValue != DBNull.Value)
returnValue = Convert.ToBoolean(blValue);
return returnValue;
}
#endregion ConvertToList
方法2 - 從手動映射像下面
手冊映射到對象從數據表建模。在這種方法中，我們需要爲每個映射編寫這種方法。
List<Student> studentList = new List<Student>();
for (int i = 0; i < dt.Rows.Count; i++)
{
Student student = new Student();
student.StudentId = Convert .ToInt32 (dt.Rows[i]["StudentId"]);
student.StudentName = dt.Rows[i]["StudentName"].ToString();
student.Address = dt.Rows[i]["Address"].ToString();
student.MobileNo = dt.Rows[i]["MobileNo"].ToString();
studentList.Add(student);
}
我的問題 -在轉換的這種通用的方式使得對性能的影響？我是否應該切換到像方法2之類的對象的正常手動映射？是方法2增強性能？
當然，它會影響性能。你應該決定這種影響在你的情況下是否可以接受。你也可以使用面向性能的ORM（比如Dapper），它會爲你做動態轉換（並且最可能比所提供的代碼示例更好）。 – Evk
通過反射訪問所有內容可能會慢很多，是的。在你的應用程序中這是否意義重大是另一回事。請注意，已經有很多映射庫可用 - 我猜想其中一個可以滿足您的需求，而且它們可能比您當前的代碼更加優化。 –
你可以嘗試使用AutoMapper（http://automapper.org/） –