您可以使用DbDataReader 作为 SQL 参数的值。因此，我们的想法是将IEnumerable<T> 转换为DbDataReader。
public class ObjectDataReader<T> : DbDataReader
{
private bool _iteratorOwned;
private IEnumerator<T> _iterator;
private IDictionary<string, int> _propertyNameToOrdinal = new Dictionary<string, int>();
private IDictionary<int, string> _ordinalToPropertyName = new Dictionary<int, string>();
private Func<T, object>[] _getPropertyValueFuncs;
public ObjectDataReader(IEnumerable<T> enumerable)
{
if (enumerable == null) throw new ArgumentNullException(nameof(enumerable));
_iteratorOwned = true;
_iterator = enumerable.GetEnumerator();
_iterator.MoveNext();
Initialize();
}
public ObjectDataReader(IEnumerator<T> iterator)
{
if (iterator == null) throw new ArgumentNullException(nameof(iterator));
_iterator = iterator;
Initialize();
}
protected override void Dispose(bool disposing)
{
if (disposing && _iteratorOwned)
{
if(_iterator != null)
_iterator.Dispose();
}
base.Dispose(disposing);
}
private void Initialize()
{
int ordinal = 0;
var properties = typeof(T).GetProperties();
_getPropertyValueFuncs = new Func<T, object>[properties.Length];
foreach (var property in properties)
{
string propertyName = property.Name;
_propertyNameToOrdinal.Add(propertyName, ordinal);
_ordinalToPropertyName.Add(ordinal, propertyName);
var parameterExpression = Expression.Parameter(typeof(T), "x");
var func = (Func<T, object>)Expression.Lambda(Expression.Convert(Expression.Property(parameterExpression, propertyName), typeof(object)), parameterExpression).Compile();
_getPropertyValueFuncs[ordinal] = func;
ordinal++;
}
}
public override object this[int ordinal]
{
get
{
return GetValue(ordinal);
}
}
public override object this[string name]
{
get
{
return GetValue(GetOrdinal(name));
}
}
public override int Depth => 1;
public override int FieldCount => _ordinalToPropertyName.Count;
public override bool HasRows => true;
public override bool IsClosed
{
get
{
return _iterator != null;
}
}
public override int RecordsAffected
{
get
{
throw new NotImplementedException();
}
}
public override bool GetBoolean(int ordinal)
{
return (bool)GetValue(ordinal);
}
public override byte GetByte(int ordinal)
{
return (byte)GetValue(ordinal);
}
public override long GetBytes(int ordinal, long dataOffset, byte[] buffer, int bufferOffset, int length)
{
throw new NotImplementedException();
}
public override char GetChar(int ordinal)
{
return (char)GetValue(ordinal);
}
public override long GetChars(int ordinal, long dataOffset, char[] buffer, int bufferOffset, int length)
{
throw new NotImplementedException();
}
public override string GetDataTypeName(int ordinal)
{
throw new NotImplementedException();
}
public override DateTime GetDateTime(int ordinal)
{
return (DateTime)GetValue(ordinal);
}
public override decimal GetDecimal(int ordinal)
{
return (decimal)GetValue(ordinal);
}
public override double GetDouble(int ordinal)
{
return (double)GetValue(ordinal);
}
public override IEnumerator GetEnumerator()
{
throw new NotImplementedException();
}
public override Type GetFieldType(int ordinal)
{
var value = GetValue(ordinal);
if (value == null)
return typeof(object);
return value.GetType();
}
public override float GetFloat(int ordinal)
{
return (float)GetValue(ordinal);
}
public override Guid GetGuid(int ordinal)
{
return (Guid)GetValue(ordinal);
}
public override short GetInt16(int ordinal)
{
return (short)GetValue(ordinal);
}
public override int GetInt32(int ordinal)
{
return (int)GetValue(ordinal);
}
public override long GetInt64(int ordinal)
{
return (long)GetValue(ordinal);
}
public override string GetName(int ordinal)
{
string name;
if (_ordinalToPropertyName.TryGetValue(ordinal, out name))
return name;
return null;
}
public override int GetOrdinal(string name)
{
int ordinal;
if (_propertyNameToOrdinal.TryGetValue(name, out ordinal))
return ordinal;
return -1;
}
public override string GetString(int ordinal)
{
return (string)GetValue(ordinal);
}
public override object GetValue(int ordinal)
{
var func = _getPropertyValueFuncs[ordinal];
return func(_iterator.Current);
}
public override int GetValues(object[] values)
{
int max = Math.Min(values.Length, FieldCount);
for (var i = 0; i < max; i++)
{
values[i] = IsDBNull(i) ? DBNull.Value : GetValue(i);
}
return max;
}
public override bool IsDBNull(int ordinal)
{
return GetValue(ordinal) == null;
}
public override bool NextResult()
{
return false;
}
public override bool Read()
{
return _iterator.MoveNext();
}
}
那么，你就可以使用这个类了：
static void Main(string[] args)
{
Console.WriteLine("Hello World!");
string connectionString = "Server=(local);Database=Sample;Trusted_Connection=True;";
using (var connection = new SqlConnection(connectionString))
{
connection.Open();
using (var command = connection.CreateCommand())
{
command.CommandType = System.Data.CommandType.StoredProcedure;
command.CommandText = "procMergePageView";
var p1 = command.CreateParameter();
command.Parameters.Add(p1);
p1.ParameterName = "@Display";
p1.SqlDbType = System.Data.SqlDbType.Structured;
var items = PageViewTableType.Generate(100);
using (DbDataReader dr = new ObjectDataReader<PageViewTableType>(items))
{
p1.Value = dr;
command.ExecuteNonQuery();
}
}
}
}
class PageViewTableType
{
// Must match the name of the column of the TVP
public long PageViewID { get; set; }
// Generate dummy data
public static IEnumerable<PageViewTableType> Generate(int count)
{
for (int i = 0; i < count; i++)
{
yield return new PageViewTableType { PageViewID = i };
}
}
}
SQL 脚本：
CREATE TABLE dbo.PageView
(
PageViewID BIGINT NOT NULL CONSTRAINT pkPageView PRIMARY KEY CLUSTERED,
PageViewCount BIGINT NOT NULL
);
GO
CREATE TYPE dbo.PageViewTableType AS TABLE
(
PageViewID BIGINT NOT NULL
);
GO
CREATE PROCEDURE dbo.procMergePageView
@Display dbo.PageViewTableType READONLY
AS
BEGIN
MERGE INTO dbo.PageView AS T
USING @Display AS S
ON T.PageViewID = S.PageViewID
WHEN MATCHED THEN UPDATE SET T.PageViewCount = T.PageViewCount + 1
WHEN NOT MATCHED THEN INSERT VALUES(S.PageViewID, 1);
END
顺便说一句，我写了一个blog post about the ObjectDataReader<T>