/// <summary>
/// 返回指定类型的对象，其值等效于指定对象。
/// </summary>
/// <param name="context"> </param>
/// <param name="input"> 需要转换类型的对象 </param>
/// <param name="outputType"> 换转后的类型 </param>
/// <param name="success"> 是否成功 </param>
protected T BaseChangeType(ConvertContext context, object input, Type outputType, out bool success)
{
if ((input == null) || input is DBNull)
{
return(ChangeType(context, input, outputType, out success));
}
var str = input as string;
if (str != null)
{
return(BaseChangeType(context, str, outputType, out success));
}
success = false;
try
{
//类型相同直接转换
if (outputType.IsInstanceOfType(input))
{
success = true;
return((T)input);
}
//子类转换逻辑
var result = ChangeType(context, input, outputType, out success);
if (success)
{
return(result);
}
if (ShouldConvertString)
{
var snapshot = context.Snapshot();
//尝试转string后转换
str = input.ToString();
context.AddException($"尝试将{input.GetType()}转为字符串 = \"{str}\"");
result = ((IConvertor <T>) this).ChangeType(context, str, outputType, out success);
if (success)
{
snapshot.Recovery();
}
return(result);
}
else
{
return(default(T));
}
}
finally
{
if (success == false)
{
context.AddCastFailException(input, outputType);
}
}
}
/// <summary>
/// 返回指定类型的对象，其值等效于指定字符串对象。
/// </summary>
/// <param name="context"> </param>
/// <param name="input"> 需要转换类型的字符串对象 </param>
/// <param name="outputType"> 换转后的类型 </param>
/// <param name="success"> 是否成功 </param>
protected T BaseChangeType(ConvertContext context, string input, Type outputType, out bool success)
{
T result;
var snapshot = context.Snapshot();
if (input == null)
{
//是否可以为null
result = ChangeType(context, (object)null, outputType, out success);
}
else
{
result = ChangeType(context, input, outputType, out success);
}
if (success)
{
snapshot.Recovery();
}
else
{
context.AddCastFailException(input, outputType);
}
return(result);
}
