当前项目需要记录变更记录，即用户在进行编辑后，将变更操作记录下来。但是数据没有发生变化，则不记录。
代码1：（仅仅返回是否变化的标识）
/// <summary>
/// 反射对比实体属性变更
/// </summary>
/// <typeparam name="T"></typeparam>
public class CompareEntry<T>
{
/// <summary>
/// 编辑之前的对象和编辑后的对象进行对比
/// </summary>
/// <returns></returns>
public bool CompareDTO(T BeforeDTO, T AfterDTO)
{
bool IsEqual = true; if (BeforeDTO == null || AfterDTO == null)
{
IsEqual = false;
}
else if (BeforeDTO.Equals(DBNull.Value) || AfterDTO.Equals(DBNull.Value))
{
IsEqual = false;
}else if (BeforeDTO.GetType() != AfterDTO.GetType())
{
IsEqual = false;
return IsEqual;
}
else if (BeforeDTO is int || BeforeDTO is short || BeforeDTO is long || BeforeDTO is float || BeforeDTO is double || BeforeDTO is decimal)
{
//int 01与1
if (BeforeDTO is int)
{
if (Convert.ToInt32(BeforeDTO) != Convert.ToInt32(AfterDTO))
{
IsEqual = false;
}
}
else if (BeforeDTO is short)
{
if (Convert.ToInt16(BeforeDTO) != Convert.ToInt16(AfterDTO))
{
IsEqual = false;
}
}
else if (BeforeDTO is long)
{
if (Convert.ToInt64(BeforeDTO) != Convert.ToInt64(AfterDTO))
{
IsEqual = false;
}
}
else if (BeforeDTO is float)
{
if (Convert.ToSingle(BeforeDTO) != Convert.ToSingle(AfterDTO))
{
IsEqual = false;
}
}
else if (BeforeDTO is double)
{
if (Convert.ToDouble(BeforeDTO) != Convert.ToDouble(AfterDTO))
{
IsEqual = false;
}
}
else if (BeforeDTO is decimal)
{
if (Convert.ToDecimal(BeforeDTO) == Convert.ToDecimal(AfterDTO))
{
IsEqual = false;
}
}
}
else
{
var beforeMembers = BeforeDTO.GetType().GetProperties();
var afterMembers = AfterDTO.GetType().GetProperties();
for (int i = ; i < beforeMembers.Length; i++)
{
var beforeVal = beforeMembers[i].GetValue(BeforeDTO, null);
var afterVal = afterMembers[i].GetValue(AfterDTO, null);
var beforeValue = beforeVal == null ? null : beforeVal.ToString();
var afterValue = afterVal == null ? null : afterVal.ToString();
if (beforeValue != afterValue)
{
IsEqual = false;
break;
}
}
} return IsEqual;
}
}
调整后的代码：（返回标识以及详细变更记录）
/// <summary>
///
/// </summary>
public class CompareResult
{
/// <summary>
///
/// </summary>
public bool IsChange { get; set; }
/// <summary>
/// 变跟内容
/// </summary>
public string ChangeContent { get; set; }
} /// <summary>
/// 对比实体属性变更(利用反射)
/// </summary>
public class CompareEntry
{
/// <summary>
///
/// </summary>
/// <returns></returns>
public CompareResult CompareDTO(object BeforeDTO, object AfterDTO)
{
CompareResult result = new CompareResult();
bool b = false; if (BeforeDTO == null && AfterDTO != null)
{
b = true;
}
else if (BeforeDTO != null && AfterDTO == null)
{
b = true;
}
else if (BeforeDTO.Equals(DBNull.Value) && !AfterDTO.Equals(DBNull.Value))
{
b = true;
}
else if (!BeforeDTO.Equals(DBNull.Value) && AfterDTO.Equals(DBNull.Value))
{
b = true;
}
else if (BeforeDTO.GetType() != AfterDTO.GetType())
{
result.IsChange = true;
return result;
}
else if (BeforeDTO is int || BeforeDTO is short || BeforeDTO is long || BeforeDTO is float || BeforeDTO is double || BeforeDTO is decimal)
{
if (BeforeDTO is int)
{
if (Convert.ToInt32(BeforeDTO) != Convert.ToInt32(AfterDTO))
{
b = true;
}
}
else if (BeforeDTO is short)
{
if (Convert.ToInt16(BeforeDTO) != Convert.ToInt16(AfterDTO))
{
b = true;
}
}
else if (BeforeDTO is long)
{
if (Convert.ToInt64(BeforeDTO) != Convert.ToInt64(AfterDTO))
{
b = true;
}
}
else if (BeforeDTO is float)
{
if (Convert.ToSingle(BeforeDTO) != Convert.ToSingle(AfterDTO))
{
b = true;
}
}
else if (BeforeDTO is double)
{
if (Convert.ToDouble(BeforeDTO) != Convert.ToDouble(AfterDTO))
{
b = true;
}
}
else if (BeforeDTO is decimal)
{
if (Convert.ToDecimal(BeforeDTO) == Convert.ToDecimal(AfterDTO))
{
b = true;
}
}
}
else
{
StringBuilder content = new StringBuilder();
var beforeMembers = BeforeDTO.GetType().GetProperties();
var afterMembers = AfterDTO.GetType().GetProperties();
for (int i = ; i < beforeMembers.Length; i++)
{
var beforeVal = beforeMembers[i].GetValue(BeforeDTO, null);
var afterVal = afterMembers[i].GetValue(AfterDTO, null);
var beforeValue = beforeVal == null ? null : beforeVal.ToString();
var afterValue = afterVal == null ? null : afterVal.ToString();
if (beforeValue != afterValue)
{
b = true;
content.Append(beforeMembers[i].Name+"("+ beforeValue+"->"+afterValue+")");
}
}
result.IsChange = b;
result.ChangeContent = content.ToString();
} return result;
}
}
注意，引用类型进行对比的时候，需要在编辑之前对对象进行拷贝，让拷贝的对象与编辑后的对象进行对比。(因为引用类型不同于值类型，值类型每次操作都会产生一个新的对象，而引用类型在new一个新对象赋值时，其实是在堆上创建了一个内存地址，指向的仍然是原对象，对它操作原对象也会发生变化。所以只有通过拷贝复制一个新对象)