VB.Net/Database ADO.net/DataColumn

Create primary key DataColumn

  
Imports System.Data
Imports System.Windows.Forms
Public Class Form1
    Inherits System.Windows.Forms.Form
    Public Shared Sub Main()
        Application.Run(New Form1())
    End Sub
    Public Sub New()
        MyBase.New()
        Me.DataGrid1 = New System.Windows.Forms.DataGrid()
        CType(Me.DataGrid1, System.ruponentModel.ISupportInitialize).BeginInit()
        Me.SuspendLayout()
        "
        Me.DataGrid1.DataMember = ""
        Me.DataGrid1.HeaderForeColor = System.Drawing.SystemColors.ControlText
        Me.DataGrid1.Location = New System.Drawing.Point(0, 8)
        Me.DataGrid1.Size = New System.Drawing.Size(432, 256)
        Me.DataGrid1.TabIndex = 0
        "
        Me.AutoScaleBaseSize = New System.Drawing.Size(5, 13)
        Me.ClientSize = New System.Drawing.Size(440, 273)
        Me.Controls.AddRange(New System.Windows.Forms.Control() {Me.DataGrid1})
        CType(Me.DataGrid1, System.ruponentModel.ISupportInitialize).EndInit()
        Me.ResumeLayout(False)
    End Sub
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        CreateCustomersTable()
    End Sub
    Private Sub dcConstructorsTest()
        Dim custTable As DataTable = New DataTable("Customers")
        Dim dtSet As DataSet = New DataSet()
        Dim myDataType As System.Type
        myDataType = System.Type.GetType("System.Int32")
        Dim priceCol As DataColumn = New DataColumn("Price", myDataType)
        priceCol.Caption = "Price"
        custTable.Columns.Add(priceCol)
        Dim qtCol As DataColumn = New DataColumn()
        qtCol.ColumnName = "Quantity"
        qtCol.DataType = System.Type.GetType("System.Int32")
        qtCol.Caption = "Quantity"
        custTable.Columns.Add(qtCol)
        Dim strExpr As String = "Price * Quantity"
        Dim totCol As DataColumn = New DataColumn("Total", myDataType, strExpr, MappingType.Attribute)
        totCol.Caption = "Total"
        custTable.Columns.Add(totCol)
        dtSet.Tables.Add(custTable)
        DataGrid1.SetDataBinding(dtSet, "Customers")
    End Sub
    Private Sub CreateCustTable()
        Dim custTable As DataTable = New DataTable("Customers")
        Dim IdCol As DataColumn = New DataColumn()
        IdCol.ColumnName = "ID"
        IdCol.DataType = Type.GetType("System.Int32")
        IdCol.ReadOnly = True
        IdCol.AllowDBNull = False
        IdCol.Unique = True
        IdCol.AutoIncrement = True
        IdCol.AutoIncrementSeed = 1
        IdCol.AutoIncrementStep = 1
        custTable.Columns.Add(IdCol)
        Dim nameCol As DataColumn = New DataColumn()
        nameCol.ColumnName = "Name"
        nameCol.DataType = Type.GetType("System.String")
        custTable.Columns.Add(nameCol)
        Dim addCol As DataColumn = New DataColumn()
        addCol.ColumnName = "Address"
        addCol.DataType = Type.GetType("System.String")
        custTable.Columns.Add(addCol)
        Dim dobCol As DataColumn = New DataColumn()
        dobCol.ColumnName = "DOB"
        dobCol.DataType = Type.GetType("System.DateTime")
        custTable.Columns.Add(dobCol)
        Dim fullTimeCol As DataColumn = New DataColumn()
        fullTimeCol.ColumnName = "VAR"
        fullTimeCol.DataType = Type.GetType("System.Boolean")
        custTable.Columns.Add(fullTimeCol)
        Dim PrimaryKeyColumns() As DataColumn = New DataColumn(1) {}
        PrimaryKeyColumns(0) = custTable.Columns("ID")
        custTable.PrimaryKey = PrimaryKeyColumns
        Dim ds As DataSet = New DataSet("Customers")
        ds.Tables.Add(custTable)
        dataGrid1.DataSource = ds.DefaultViewManager
    End Sub
    Private Sub CreateCustomersTable()
        Dim custTable As System.Data.DataTable = New DataTable("Customers")
        Dim dtColumn As DataColumn
        dtColumn = New DataColumn()
        dtColumn.DataType = System.Type.GetType("System.Int32")
        dtColumn.ColumnName = "id"
        dtColumn.Caption = "Cust ID"
        dtColumn.ReadOnly = True
        dtColumn.Unique = True
        custTable.Columns.Add(dtColumn)
        dtColumn = New DataColumn()
        dtColumn.DataType = System.Type.GetType("System.String")
        dtColumn.ColumnName = "Name"
        dtColumn.Caption = "Cust Name"
        dtColumn.AutoIncrement = False
        dtColumn.ReadOnly = False
        dtColumn.Unique = False
        custTable.Columns.Add(dtColumn)
        dtColumn = New DataColumn()
        dtColumn.DataType = System.Type.GetType("System.String")
        dtColumn.ColumnName = "Address"
        dtColumn.Caption = "Address"
        dtColumn.ReadOnly = False
        dtColumn.Unique = False
        custTable.Columns.Add(dtColumn)
        Dim PrimaryKeyColumns() As DataColumn = New DataColumn(1) {}
        PrimaryKeyColumns(0) = custTable.Columns("id")
        custTable.PrimaryKey = PrimaryKeyColumns
        Dim ds As DataSet = New DataSet("Customers")
        ds.Tables.Add(custTable)
        Dim row1 As DataRow = custTable.NewRow()
        row1("id") = 1001
        row1("Address") = "CA"
        row1("Name") = "A"
        custTable.Rows.Add(row1)
        Dim row2 As DataRow = custTable.NewRow()
        row2("id") = 1002
        row2("Name") = "R"
        row2("Address") = "CA"
        custTable.Rows.Add(row2)
        Dim row3 As DataRow = custTable.NewRow()
        row3("id") = 1003
        row3("Name") = "M "
        row3("Address") = "CA"
        custTable.Rows.Add(row3)
        MessageBox.Show(row2.RowState.ToString())
        row2.Delete()
        MessageBox.Show(row3.RowState.ToString())
        DataGrid1.DataSource = ds.DefaultViewManager
    End Sub
    Friend WithEvents DataGrid1 As System.Windows.Forms.DataGrid
End Class

DataColumn Collection demo

  
Imports System.Data
Imports System.Windows.Forms
Public Class Form1
    Inherits System.Windows.Forms.Form
    Private custTable As DataTable
    Private dtSet As DataSet
    Public Shared Sub Main()
        Application.Run(New Form1())
    End Sub

    Public Sub New()
        MyBase.New()
        InitializeComponent()
    End Sub
    Friend WithEvents DataGrid1 As System.Windows.Forms.DataGrid
    <System.Diagnostics.DebuggerStepThrough()> Private Sub InitializeComponent()
        Me.DataGrid1 = New System.Windows.Forms.DataGrid()
        CType(Me.DataGrid1, System.ruponentModel.ISupportInitialize).BeginInit()
        Me.SuspendLayout()
        Me.DataGrid1.DataMember = ""
        Me.DataGrid1.Location = New System.Drawing.Point(16, 8)
        Me.DataGrid1.Size = New System.Drawing.Size(264, 256)
        Me.DataGrid1.TabIndex = 0
        "
        "Form1
        "
        Me.AutoScaleBaseSize = New System.Drawing.Size(5, 13)
        Me.ClientSize = New System.Drawing.Size(292, 273)
        Me.Controls.AddRange(New System.Windows.Forms.Control() {Me.DataGrid1})
        CType(Me.DataGrid1, System.ruponentModel.ISupportInitialize).EndInit()
        Me.ResumeLayout(False)
    End Sub
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        custTable = New DataTable("Customers")
        Dim dtColumn As DataColumn
        Dim myDataRow As DataRow
        dtColumn = New DataColumn()
        dtColumn.DataType = System.Type.GetType("System.Int32")
        dtColumn.ColumnName = "id"
        dtColumn.Caption = "Cust ID"
        dtColumn.ReadOnly = False
        dtColumn.Unique = True
        custTable.Columns.Add(dtColumn)
        " Create Name column.
        dtColumn = New DataColumn()
        dtColumn.DataType = System.Type.GetType("System.String")
        dtColumn.ColumnName = "Name"
        dtColumn.Caption = "Cust Name"
        dtColumn.AutoIncrement = False
        dtColumn.ReadOnly = False
        dtColumn.Unique = False
        custTable.Columns.Add(dtColumn)
        dtColumn = New DataColumn()
        dtColumn.DataType = System.Type.GetType("System.String")
        dtColumn.ColumnName = "Address"
        dtColumn.Caption = "Address"
        dtColumn.ReadOnly = False
        dtColumn.Unique = False
        custTable.Columns.Add(dtColumn)
        Dim PrimaryKeyColumns() As DataColumn = New DataColumn(1) {}
        PrimaryKeyColumns(0) = custTable.Columns("id")
        custTable.PrimaryKey = PrimaryKeyColumns
        dtSet = New DataSet("Customers")
        dtSet.Tables.Add(custTable)
        myDataRow = custTable.NewRow()
        myDataRow("id") = 1001
        myDataRow("Address") = "CA"
        myDataRow("Name") = "A"
        custTable.Rows.Add(myDataRow)
        myDataRow = custTable.NewRow()
        myDataRow("id") = 1002
        myDataRow("Name") = "Jack "
        myDataRow("Address") = "CA"
        custTable.Rows.Add(myDataRow)
        myDataRow = custTable.NewRow()
        myDataRow("id") = 1003
        myDataRow("Name") = "M"
        myDataRow("Address") = "BC"
        custTable.Rows.Add(myDataRow)
        Dim cols As DataColumnCollection = custTable.Columns
        Dim str As String
        str = cols.Count.ToString()
        MessageBox.Show(str)
        If cols.Contains("Name") Then
            If cols.CanRemove(cols("Name")) Then
                cols.Remove("Name")
            End If
        End If
        DataGrid1.DataSource = dtSet.DefaultViewManager
    End Sub
End Class