public static object ConvertTo(this object vt, Type toType)
{
if (vt == null)
{
return(GetDefault(toType));
}
Type fromType = vt.GetType();
if (fromType == typeof(DBNull))
{
return(GetDefault(toType));
}
if (fromType == typeof(ExcelEmpty) || fromType == typeof(ExcelError) || fromType == typeof(ExcelMissing))
{
return(GetDefault(toType));
}
if (fromType == typeof(ExcelReference))
{
var r = (ExcelReference)vt;
object val = r.GetValue();
return(ConvertTo(val, toType));
}
//acount for nullable types
toType = Nullable.GetUnderlyingType(toType) ?? toType;
if (toType == typeof(DateTime))
{
DateTime dt = DateTime.FromOADate(0.0);
if (fromType == typeof(DateTime))
{
dt = (DateTime)vt;
}
else if (fromType == typeof(double))
{
dt = DateTime.FromOADate((double)vt);
}
else if (fromType == typeof(string))
{
DateTime result;
if (DateTime.TryParse((string)vt, out result))
{
dt = result;
}
}
return(Convert.ChangeType(dt, toType));
}
if (toType == typeof(XlDate))
{
XlDate dt = 0.0;
if (fromType == typeof(DateTime))
{
dt = (DateTime)vt;
}
else if (fromType == typeof(double))
{
dt = (double)vt;
}
else if (fromType == typeof(string))
{
DateTime result;
if (DateTime.TryParse((string)vt, out result))
{
dt = result;
}
else
{
dt = 0.0;
}
}
else
{
dt = (double)Convert.ChangeType(vt, typeof(double));
}
return(Convert.ChangeType(dt, toType));
}
if (toType == typeof(double))
{
double dt = 0.0;
if (fromType == typeof(double))
{
dt = (double)vt;
}
else if (fromType == typeof(DateTime))
{
dt = ((DateTime)vt).ToOADate();
}
else if (fromType == typeof(string))
{
double.TryParse((string)vt, out dt);
}
else
{
dt = (double)Convert.ChangeType(vt, typeof(double));
}
return(Convert.ChangeType(dt, toType));
}
if (toType.IsEnum)
{
try{
return(Enum.Parse(toType, vt.ToString(), true));
} catch (Exception) {
return(GetDefault(toType));
}
}
return(Convert.ChangeType(vt, toType));
}
public XlDate(XlDate xlDate)
{
_xlDate = xlDate._xlDate;
_dateTime = xlDate._dateTime;
}
/// <summary>
/// 类型转换
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="vt"></param>
/// <returns></returns>
public static T ConvertTo <T>(this object vt)
{
if (vt.IsNull())
{
return(default(T));
}
Type toType = typeof(T);
Type fromType = vt.GetType();
var reference = vt as ExcelReference;
if (reference != null)
{
object val = reference.GetValue();
return(ConvertTo <T>(val));
}
//acount for nullable types
toType = Nullable.GetUnderlyingType(toType) ?? toType;
if (toType == typeof(DateTime))
{
DateTime dt = DateTime.FromOADate(0.0);
if (fromType == typeof(DateTime))
{
dt = (DateTime)vt;
}
else if (fromType == typeof(double))
{
dt = DateTime.FromOADate((double)vt);
}
else if (fromType == typeof(string))
{
if (DateTime.TryParse((string)vt, out var result))
{
dt = result;
}
}
//note this will work also if T is nullable
return((T)Convert.ChangeType(dt, toType));
}
if (toType == typeof(XlDate))
{
XlDate dt = 0.0;
if (fromType == typeof(DateTime))
{
dt = (DateTime)vt;
}
else if (fromType == typeof(double))
{
dt = (double)vt;
}
else if (fromType == typeof(string))
{
if (DateTime.TryParse((string)vt, out var result))
{
dt = result;
}
else
{
dt = 0.0;
}
}
else
{
dt = (double)Convert.ChangeType(vt, typeof(double));
}
return((T)Convert.ChangeType(dt, toType));
}
if (toType == typeof(double))
{
double dt = 0.0;
if (fromType == typeof(double))
{
dt = (double)vt;
}
else if (fromType == typeof(DateTime))
{
dt = ((DateTime)vt).ToOADate();
}
else if (fromType == typeof(string))
{
double.TryParse((string)vt, out dt);
}
else
{
dt = (double)Convert.ChangeType(vt, typeof(double));
}
return((T)Convert.ChangeType(dt, toType));
}
if (toType.IsEnum)
{
try{
return((T)Enum.Parse(typeof(T), vt.ToString(), true));
} catch (Exception) {
return(default(T));
}
}
return((T)Convert.ChangeType(vt, toType));
}
