public static IDbValueReader GetDbValueReader(Type type)
{
var handler = GetValueHandlerCache.GetOrAdd(type, valueType =>
{
valueType = valueType.GetUnderlyingType();
if (valueType.IsEnum)
{
return(new DbValueReader((IDataReader reader, int ordinal) =>
{
object value = reader.GetEnum(ordinal, valueType);
return value;
}));
}
Infrastructure.MappingType mappingType = MappingTypeSystem.GetMappingType(valueType);
return(new DbValueReader((IDataReader reader, int ordinal) =>
{
object value = DataReaderExtension.GetValue(reader, ordinal);
if (value == null)
{
return null;
}
if (value.GetType() == mappingType.Type)
{
return value;
}
return mappingType.DbValueConverter.Convert(value);
}));
});
return(handler);
}
protected virtual IDbCommand PrepareCommand(string cmdText, DbParam[] parameters, CommandType cmdType, out List <OutputParameter> outputParameters)
{
outputParameters = null;
IDbCommand cmd = this.DbConnection.CreateCommand();
cmd.CommandText = cmdText;
cmd.CommandType = cmdType;
cmd.CommandTimeout = this.CommandTimeout;
if (this.IsInTransaction)
{
cmd.Transaction = this.DbTransaction;
}
if (parameters != null)
{
for (int i = 0; i < parameters.Length; i++)
{
DbParam param = parameters[i];
if (param == null)
{
continue;
}
if (param.ExplicitParameter != null)/* 如果存在创建好了的 IDbDataParameter，则直接用它。同时也忽视了 DbParam 的其他属性 */
{
cmd.Parameters.Add(param.ExplicitParameter);
continue;
}
Type parameterType;
if (param.Value == null || param.Value == DBNull.Value)
{
parameterType = param.Type ?? typeof(object);
}
else
{
parameterType = param.Value.GetType();
if (parameterType.IsEnum)
{
parameterType = Enum.GetUnderlyingType(parameterType);
}
}
IDbDataParameter parameter = cmd.CreateParameter();
Infrastructure.MappingType mappingType = MappingTypeSystem.GetMappingType(parameterType);
mappingType.DbParameterAssembler.SetupParameter(parameter, param);
cmd.Parameters.Add(parameter);
OutputParameter outputParameter = null;
if (param.Direction == ParamDirection.Output || param.Direction == ParamDirection.InputOutput)
{
outputParameter = new OutputParameter(param, parameter);
if (outputParameters == null)
{
outputParameters = new List <OutputParameter>();
}
outputParameters.Add(outputParameter);
}
}
}
return(cmd);
}