The DataColumn Class

The DataColumn Class

You use an object of the DataColumn class to represent a column. You can also store multiple DataColumn objects in a DataRow. Table 11.6 shows some of the DataColumn properties.

Table 11.6: DataColumn PROPERTIES

PROPERTY

TYPE

DESCRIPTION

AllowDBNull

bool

Gets or sets a bool value that indicates whether null values are allowed in this DataColumn object. The default is true.

AutoIncrement

bool

Gets or sets a bool value that indicates whether the DataColumn object automatically increments the value of the column for new rows. The default is false.

AutoIncrementSeed

long

Gets or sets the starting value for the DataColumn object. Applies only when the AutoIncrement property is set to true. The default is 0.

AutoIncrementStep

long

Gets or sets the increment used. Applies only when the AutoIncrement property is set to true. The default is 1.

Caption

string

Gets or sets the caption for the column. The caption for the column is shown in Windows forms. The default is null.

ColumnName

string

Gets or sets the name of the DataColumn object.

ColumnMapping

MappingType

Gets or sets the MappingType of the DataColumn object. This determines how a DataColumn is saved in an XML document using the WriteXml() method.

DataType

Type

Gets or sets the .NET data type used to represent the 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.

DafaultValue

object

Gets or sets the default value for the DataColumn when new rows are created. When AutoIncrement is set to true, DefaultValue is not used.

MaxLength

int

Gets or sets the maximum length of text that may be stored in a DataColumn object. The default is -1.

Ordinal

int

Gets the numeric position of the DataColumn object (0 is the first object).

ReadOnly

bool

Gets or sets a bool value that indicates whether the DataColumn object can be changed once it has been added to a DataRow. The default is false.

Table

DataTable

Gets the DataTable to which the DataColumn object belongs.

Unique

bool

Gets or sets a bool value that indicates whether the 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.




Mastering C# Database Programming
Mastering the SAP Business Information Warehouse: Leveraging the Business Intelligence Capabilities of SAP NetWeaver
ISBN: 0764596373
EAN: 2147483647
Year: 2003
Pages: 181

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