IsBlank Function |  |
-- todo --
Determines whether an expression is blank.
Namespace: XSharp.VFP
Assembly: XSharp.VFP (in XSharp.VFP.dll) Version: 2.21
SyntaxRequest Example
View Source
Logical. IsBlank( ) returns True (.T.) if the expression eExpression is blank; otherwise, IsBlank( ) returns False (.F.).
IsBlank( ) returns True (.T.) for fields when those fields contain certain values. The table below lists the values that field types contain for IsBlank( ) to return True.
Parameters
- eExpression (Optional)
- Type: Usual
Specifies the expression for IsBlank( ) to evaluate. eExpression can be a field in a table, a variable or array element, or an expression.
Return Value
Type: LogicLogical. IsBlank( ) returns True (.T.) if the expression eExpression is blank; otherwise, IsBlank( ) returns False (.F.).
IsBlank( ) returns True (.T.) for fields when those fields contain certain values. The table below lists the values that field types contain for IsBlank( ) to return True.
| Data type | Values the field contains |
|---|---|
| Blob | Empty (0h) or contains only zero bytes, for example, 0h00, 0h000000, and so on |
| Character | Empty string, spaces, or no value, such as a newly appended blank record or cleared with Blank |
| Date | Blank date ({ / / }) or no value, such as a newly appended blank record or cleared with Blank |
| DateTime | Blank datetime ({ / / : : }) or no value, such as a newly appended blank record or cleared with Blank |
| Float | No value, such as a newly appended blank record or cleared with Blank |
| General | Empty, for example, no OLE object |
| Logical | No value, such as a newly appended blank record or cleared with Blank |
| Memo | Empty, for example, no memo contents |
| Numeric | No value, such as a newly appended blank record or cleared with Blank |
| Varbinary | Empty (0h) or contains only zero bytes, for example, 0h00, 0h000000, and so on |
 Note |
|---|
| Expressions with Currency, Integer, or Double type are never blank; therefore, IsBlank( ) always returns False (.F.) for these expression types. |
Remarks
To create a blank record, use the Append Blank and Blank commands.
You can also use Blank to clear data from fields in a record.
IsBlank( ) differs from Empty( ) and IsNull( ). For example, Empty( ) returns True (.T.) if a character expression evaluates to empty, for example, it contains spaces, tabs, carriage returns, or line feeds. IsBlank( ) returns True (.T.) if the character expression contains only the empty string ("") or spaces.
IsBlank( ) differs from Empty( ) and IsNull( ). For example, Empty( ) returns True (.T.) if a character expression evaluates to empty, for example, it contains spaces, tabs, carriage returns, or line feeds. IsBlank( ) returns True (.T.) if the character expression contains only the empty string ("") or spaces.
ExamplesX#
1Create Table mytable FREE (myfield C(20)) 2Append Blank // Add new blank record 3Clear 4? ISBlank(myfield) // Displays .T. 5Replace myfield WITH 'John Smith' // Insert a value in the field 6? ISBlank(myfield) // Displays .F.
See Also