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 | Tcx |
TField |
Description |
---|---|---|---|
'String' |
Tcx |
ft |
Unicode string values. |
'Wide |
Tcx |
ft |
Wide string values. |
'Smallint' |
Tcx |
ft |
16-bit signed integer values. |
'Integer' |
Tcx |
ft |
32-bit signed integer values. |
'Word' |
Tcx |
ft |
16-bit unsigned integer values. |
'Boolean' |
Tcx |
ft |
Boolean values. |
'Single' |
Tcx |
ft |
Single precision floating-point values. |
'Float' |
Tcx |
ft |
Double precision floating-point values. |
'Currency' |
Tcx |
ft |
Monetary values. |
'Date |
Tcx |
ft |
Date and time values. |
'Large |
Tcx |
ft |
64-bit signed integer values. |
'FMTBcd' |
Tcx |
ft |
Binary-encoded decimal values that can be converted to Currency without a loss of precision. |
'SQLTime |
Tcx |
ft [3] |
High-precision date and time values. |
'Variant' |
Tcx |
ft |
Values of any type. |
'BLOB' [4] |
Tcx |
fs |
BLOBs (Binary Large OBjects) as values. BLOB values are most often used for storing files in a database. |
'Object' [5] |
Tcx |
ft |
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.
Value |
Value |
Default Editor |
---|---|---|
'Boolean' |
Tcx |
Tcx |
'Currency' |
Tcx |
Tcx |
'Date |
Tcx |
Tcx |
'FMTBcd' |
Tcx |
Tcx |
'SQLTime |
Tcx |
Tcx |
Any other value | Any other value | Tcx |
-
Different
TcxValueType
class 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.