TcxValueType Class
The base class for classes that implement functionality related to different value types in DevExpress data controllers and other data-related APIs.
Declaration
TcxValueType = class(
TObject
)Remarks
The TcxValueType class has members that allow you to do the following:
- Identify the value type by its name (Caption).
- Compare values of the same type (Compare).
- Obtain the value type’s Variant code (GetVarType).
- Identify if the value type is string or numeric (IsString and IsNumeric).
- Read a value from a memory buffer (PrepareValueBuffer and GetValue).
Terminal TcxValueType Class Descendants
Do not use the TcxValueType class directly. Use the following descendants that correspond to TFieldType values:
| Caption[1] Value | TcxValueType Descendant | TFieldType[2] Value | Description |
|---|---|---|---|
'String' |
TcxStringValueType | ftString |
Unicode string values. |
'WideString' |
TcxWideStringValueType | ftWideString |
Wide string values. |
'Smallint' |
TcxSmallintValueType | ftSmallint |
16-bit signed integer values. |
'Integer' |
TcxIntegerValueType | ftInteger |
32-bit signed integer values. |
'Word' |
TcxWordValueType | ftWord |
16-bit unsigned integer values. |
'Boolean' |
TcxBooleanValueType | ftBoolean |
Boolean values. |
'Single' |
TcxSingleValueType | ftSingle |
Single precision floating-point values. |
'Float' |
TcxFloatValueType | ftFloat |
Double precision floating-point values. |
'Currency' |
TcxCurrencyValueType | ftCurrency |
Monetary values. |
'DateTime' |
TcxDateTimeValueType | ftDateTime |
Date and time values. |
'LargeInt' |
TcxLargeIntValueType | ftLargeInt |
64-bit signed integer values. |
'FMTBcd' |
TcxFMTBcdValueType | ftFMTBcd |
Binary-encoded decimal values that can be converted to Currency without a loss of precision. |
'SQLTimeStamp' |
TcxSQLTimeStampValueType | ftTimeStamp[3] |
High-precision date and time values. |
'Variant' |
TcxVariantValueType | ftVariant |
Values of any type. |
'BLOB'[4] |
TcxBLOBValueType | fsBlob |
BLOBs (Binary Large OBjects) as values. BLOB values are most often used for storing files in a database. |
'Object'[5] |
TcxObjectValueType | ftObject |
Values that store non-visual objects (TObject descendant instances) with arbitrary data for an unbound editor or Data Grid item. |
Value Type Classes and Default In-Place Editors
When a container control is in unbound mode, the corresponding ValueTypeClass or ValueType property specifies the default in-place editor.
| ValueType Value | ValueTypeClass Value | Default Editor |
|---|---|---|
'Boolean' |
TcxBooleanValueType | TcxCheckBox |
'Currency' |
TcxCurrencyValueType | TcxCurrencyEdit |
'DateTime' |
TcxDateTimeValueType | TcxDateEdit |
'FMTBcd' |
TcxFMTBcdValueType | TcxCurrencyEdit |
'SQLTimeStamp' |
TcxSQLTimeStampValueType | TcxDateEdit |
| Any other value | Any other value | TcxTextEdit |
Inheritance
-
Different
TcxValueTypeclass descendants return different caption values. -
This column lists the corresponding TFieldType values.
-
'SQLTimeStamp'also corresponds to the TSQLTimeStamp type. -
Use this value type with those controls and editors that support BLOB.
-
Use this type only in custom or inherited components because DevExpress and standard VCL components have no information on actual content of such values.