static void FixColumnType(DataColumn column)
{
if (column.DataType == typeof(object))
{
Type colType = null;
foreach (DataRow row in column.Table.Rows)
{
var value = row[column];
if (value == null || value == DBNull.Value)
{
continue;
}
var valType = value.GetType();
if (colType == null)
{
colType = valType;
}
else if (colType != valType)
{
var colTypeCode = Type.GetTypeCode(colType);
var valTypeCode = Type.GetTypeCode(valType);
switch (colTypeCode)
{
case TypeCode.Empty:
colType = valType;
break;
case TypeCode.Object:
colType = typeof(object);
break;
case TypeCode.DBNull:
colType = valType;
break;
case TypeCode.Boolean:
if (IsTypeCode(valTypeCode, TypeCode.Byte, TypeCode.SByte, TypeCode.Int16, TypeCode.UInt16, TypeCode.Int32, TypeCode.UInt32,
TypeCode.Int64, TypeCode.UInt64, TypeCode.Single, TypeCode.Double, TypeCode.Decimal, TypeCode.DateTime))
{
colType = valType;
}
else if (IsTypeCode(valTypeCode, TypeCode.Char, TypeCode.String))
{
colType = typeof(string);
}
else if (IsTypeCode(valTypeCode, TypeCode.Object))
{
colType = typeof(object);
}
break;
case TypeCode.Char:
if (IsTypeCode(valTypeCode, TypeCode.String, TypeCode.Byte, TypeCode.SByte, TypeCode.Int16, TypeCode.UInt16, TypeCode.Int32, TypeCode.UInt32,
TypeCode.Int64, TypeCode.UInt64, TypeCode.Single, TypeCode.Double, TypeCode.Decimal, TypeCode.DateTime))
{
colType = typeof(string);
}
else if (IsTypeCode(valTypeCode, TypeCode.Object))
{
colType = typeof(object);
}
break;
case TypeCode.SByte:
if (IsTypeCode(valTypeCode, TypeCode.Byte))
{
colType = typeof(short);
}
else if (IsTypeCode(valTypeCode, TypeCode.Int16, TypeCode.UInt16, TypeCode.Int32, TypeCode.UInt32,
TypeCode.Int64, TypeCode.UInt64, TypeCode.Single, TypeCode.Double, TypeCode.Decimal, TypeCode.DateTime))
{
colType = valType;
}
else if (IsTypeCode(valTypeCode, TypeCode.Char, TypeCode.String))
{
colType = typeof(string);
}
else if (IsTypeCode(valTypeCode, TypeCode.Object))
{
colType = typeof(object);
}
break;
case TypeCode.Byte:
if (IsTypeCode(valTypeCode, TypeCode.SByte))
{
colType = typeof(short);
}
else if (IsTypeCode(valTypeCode, TypeCode.Int16, TypeCode.UInt16, TypeCode.Int32, TypeCode.UInt32,
TypeCode.Int64, TypeCode.UInt64, TypeCode.Single, TypeCode.Double, TypeCode.Decimal, TypeCode.DateTime))
{
colType = valType;
}
else if (IsTypeCode(valTypeCode, TypeCode.Char, TypeCode.String))
{
colType = typeof(string);
}
else if (IsTypeCode(valTypeCode, TypeCode.Object))
{
colType = typeof(object);
}
break;
case TypeCode.Int16:
if (IsTypeCode(valTypeCode, TypeCode.Byte, TypeCode.SByte))
{
colType = typeof(short);
}
else if (IsTypeCode(valTypeCode, TypeCode.UInt16))
{
colType = typeof(int);
}
else if (IsTypeCode(valTypeCode, TypeCode.Int32, TypeCode.UInt32,
TypeCode.Int64, TypeCode.UInt64, TypeCode.Single, TypeCode.Double, TypeCode.Decimal, TypeCode.DateTime))
{
colType = valType;
}
else if (IsTypeCode(valTypeCode, TypeCode.Char, TypeCode.String))
{
colType = typeof(string);
}
else if (IsTypeCode(valTypeCode, TypeCode.Object))
{
colType = typeof(object);
}
break;
case TypeCode.UInt16:
if (IsTypeCode(valTypeCode, TypeCode.Byte, TypeCode.SByte))
{
colType = typeof(int);
}
else if (IsTypeCode(valTypeCode, TypeCode.Int16))
{
colType = typeof(int);
}
else if (IsTypeCode(valTypeCode, TypeCode.Int32, TypeCode.UInt32,
TypeCode.Int64, TypeCode.UInt64, TypeCode.Single, TypeCode.Double, TypeCode.Decimal, TypeCode.DateTime))
{
colType = valType;
}
else if (IsTypeCode(valTypeCode, TypeCode.Char, TypeCode.String))
{
colType = typeof(string);
}
else if (IsTypeCode(valTypeCode, TypeCode.Object))
{
colType = typeof(object);
}
break;
case TypeCode.Int32:
if (IsTypeCode(valTypeCode, TypeCode.Byte, TypeCode.SByte, TypeCode.Int16, TypeCode.UInt16))
{
colType = typeof(int);
}
else if (IsTypeCode(valTypeCode, TypeCode.UInt32))
{
colType = typeof(long);
}
else if (IsTypeCode(valTypeCode, TypeCode.Int64, TypeCode.UInt64, TypeCode.Single, TypeCode.Double, TypeCode.Decimal, TypeCode.DateTime))
{
colType = valType;
}
else if (IsTypeCode(valTypeCode, TypeCode.Char, TypeCode.String))
{
colType = typeof(string);
}
else if (IsTypeCode(valTypeCode, TypeCode.Object))
{
colType = typeof(object);
}
break;
case TypeCode.UInt32:
if (IsTypeCode(valTypeCode, TypeCode.Byte, TypeCode.SByte, TypeCode.Int16, TypeCode.UInt16))
{
colType = typeof(long);
}
else if (IsTypeCode(valTypeCode, TypeCode.Int32))
{
colType = typeof(long);
}
else if (IsTypeCode(valTypeCode, TypeCode.Int64, TypeCode.UInt64, TypeCode.Single, TypeCode.Double, TypeCode.Decimal, TypeCode.DateTime))
{
colType = valType;
}
else if (IsTypeCode(valTypeCode, TypeCode.Char, TypeCode.String))
{
colType = typeof(string);
}
else if (IsTypeCode(valTypeCode, TypeCode.Object))
{
colType = typeof(object);
}
break;
case TypeCode.Int64:
if (IsTypeCode(valTypeCode, TypeCode.Byte, TypeCode.SByte, TypeCode.Int16, TypeCode.UInt16, TypeCode.Int32, TypeCode.UInt32))
{
colType = typeof(long);
}
else if (IsTypeCode(valTypeCode, TypeCode.UInt64)) //anyway leave unsigned
{
colType = typeof(long);
}
else if (IsTypeCode(valTypeCode, TypeCode.Single, TypeCode.Double, TypeCode.Decimal, TypeCode.DateTime))
{
colType = valType;
}
else if (IsTypeCode(valTypeCode, TypeCode.Char, TypeCode.String))
{
colType = typeof(string);
}
else if (IsTypeCode(valTypeCode, TypeCode.Object))
{
colType = typeof(object);
}
break;
case TypeCode.UInt64:
if (IsTypeCode(valTypeCode, TypeCode.Byte, TypeCode.SByte, TypeCode.Int16, TypeCode.UInt16, TypeCode.Int32, TypeCode.UInt32))
{
colType = typeof(long);
}
else if (IsTypeCode(valTypeCode, TypeCode.Int64)) //anyway leave unsigned
{
colType = typeof(long);
}
else if (IsTypeCode(valTypeCode, TypeCode.Single, TypeCode.Double, TypeCode.Decimal, TypeCode.DateTime))
{
colType = valType;
}
else if (IsTypeCode(valTypeCode, TypeCode.Char, TypeCode.String))
{
colType = typeof(string);
}
else if (IsTypeCode(valTypeCode, TypeCode.Object))
{
colType = typeof(object);
}
break;
case TypeCode.Single:
if (IsTypeCode(valTypeCode, TypeCode.Byte, TypeCode.SByte, TypeCode.Int16, TypeCode.UInt16, TypeCode.Int32, TypeCode.UInt32,
TypeCode.Int64, TypeCode.UInt64))
{
colType = typeof(float);
}
else if (IsTypeCode(valTypeCode, TypeCode.Double))
{
colType = typeof(double);
}
else if (IsTypeCode(valTypeCode, TypeCode.Decimal, TypeCode.DateTime))
{
colType = valType;
}
else if (IsTypeCode(valTypeCode, TypeCode.Char, TypeCode.String))
{
colType = typeof(string);
}
else if (IsTypeCode(valTypeCode, TypeCode.Object))
{
colType = typeof(object);
}
break;
case TypeCode.Double:
if (IsTypeCode(valTypeCode, TypeCode.Byte, TypeCode.SByte, TypeCode.Int16, TypeCode.UInt16, TypeCode.Int32, TypeCode.UInt32,
TypeCode.Int64, TypeCode.UInt64, TypeCode.Single))
{
colType = typeof(double);
}
else if (IsTypeCode(valTypeCode, TypeCode.Decimal, TypeCode.DateTime))
{
colType = valType;
}
else if (IsTypeCode(valTypeCode, TypeCode.Char, TypeCode.String))
{
colType = typeof(string);
}
else if (IsTypeCode(valTypeCode, TypeCode.Object))
{
colType = typeof(object);
}
break;
case TypeCode.Decimal:
if (IsTypeCode(valTypeCode, TypeCode.Byte, TypeCode.SByte, TypeCode.Int16, TypeCode.UInt16, TypeCode.Int32, TypeCode.UInt32,
TypeCode.Int64, TypeCode.UInt64, TypeCode.Single, TypeCode.Double, TypeCode.DateTime))
{
colType = typeof(decimal);
}
else if (IsTypeCode(valTypeCode, TypeCode.Char, TypeCode.String))
{
colType = typeof(string);
}
else if (IsTypeCode(valTypeCode, TypeCode.Object))
{
colType = typeof(object);
}
break;
case TypeCode.DateTime:
if (IsTypeCode(valTypeCode, TypeCode.Byte, TypeCode.SByte, TypeCode.Int16, TypeCode.UInt16, TypeCode.Int32, TypeCode.UInt32,
TypeCode.Int64, TypeCode.UInt64, TypeCode.Single, TypeCode.Double, TypeCode.Decimal))
{
colType = typeof(decimal);
}
else if (IsTypeCode(valTypeCode, TypeCode.Char, TypeCode.String))
{
colType = typeof(string);
}
else if (IsTypeCode(valTypeCode, TypeCode.Object))
{
colType = typeof(object);
}
break;
case TypeCode.String:
if (IsTypeCode(valTypeCode, TypeCode.Byte, TypeCode.SByte, TypeCode.Int16, TypeCode.UInt16, TypeCode.Int32, TypeCode.UInt32,
TypeCode.Int64, TypeCode.UInt64, TypeCode.Single, TypeCode.Double, TypeCode.Decimal, TypeCode.DateTime, TypeCode.Char))
{
colType = typeof(string);
}
if (IsTypeCode(valTypeCode, TypeCode.Object))
{
colType = typeof(object);
}
break;
default:
break;
}
}
}
if (colType != null && colType != column.DataType)
{
column.ConvertColumnType(colType);
}
}
}
