/// <summary>
/// 映射下一项
/// </summary>
/// <param name="result"></param>
/// <returns></returns>
public bool MapNext(out T result)
{
if (source.Next())
{
object value = source[0];
try
{
if (value == DBNull.Value || value == null)
{
if (underlyingType != null)
{
result = default(T);
return(true);
}
}
result = (T)Convert.ChangeType(source[0], underlyingType ?? typeof(T));
}
catch (FormatException e)
{
throw new InvalidCastException($"列{source.Columns[0]}的值“{value}”无法转换为{typeof(T)}.", e);
}
catch (InvalidCastException e)
{
throw new InvalidCastException($"列{source.Columns[0]}的值“{value}”无法转换为{typeof(T)}.", e);
}
return(true);
}
result = default(T);
return(false);
}
/// <summary>
/// 映射下一结果
/// </summary>
/// <returns></returns>
public bool MapNext(out TEntity result)
{
if (!source.Next())
{
result = default(TEntity);
return(false);
}
else if (!initialized)
{
Initialize();
}
result = New();
foreach (var descriptor in mappers)
{
var columnIndex = descriptor.Key;
var description = descriptor.Value;
try
{
description.Map(result, source, columnIndex, converts[columnIndex]);
}
catch (Exception e)
{
throw new InvalidCastException($"{description.MemberName} 列映射失败，值“{source[columnIndex]}”对于类型 {description.MemberValueType} 无效", e);
}
}
return(true);
}