Tài liệu The DataColumn Class pdf

The DataColumn Class You use an object of the DataColumn class to represent a column.. Table 11.6: DataColumn PROPERTIES PROPERTY TYPE DESCRIPTION values are allowed in this DataColumn

The DataColumn Class

You use an object of the DataColumn class to represent a column You can also store

properties

Table 11.6: DataColumn PROPERTIES

PROPERTY TYPE DESCRIPTION

values are allowed in this DataColumn object The default is true

DataColumn object automatically increments the value of the column for new rows The default is false

object Applies only when the AutoIncrement property is set to true The default is 0

the AutoIncrement property is set to true The default

is 1

for the column is shown in Windows forms The default is null

object This determines how a DataColumn is saved

in an XML document using the WriteXml() method

column value stored in the DataColumn object This can be Boolean, Byte, Char, DateTime, Decimal, Double, Int16, Int32, Int64, SByte, Single, String, TimeSpan, UInt16, or UInt64

when new rows are created When AutoIncrement is set to true, DefaultValue is not used

stored in a DataColumn object The default is -1

Table 11.6: DataColumn PROPERTIES

PROPERTY TYPE DESCRIPTION

(0 is the first object)

DataColumn object can be changed once it has been added to a DataRow The default is false

belongs

DataColumn values in each DataRow object must be unique The default is false

You'll see the use of some of these properties, methods, and events later in this chapter