VB.Net by API/System.Data/DataTable

DataTable.Columns

  
Imports System
Imports System.Data
Imports System.Data.SqlClient

public class MainClass
   Shared Sub Main()
      Dim thisConnection As New SqlConnection("server=(local)\SQLEXPRESS;" & _
          "integrated security=sspi;database=MyDatabase")
      Dim sql As String = "SELECT * FROM Employee"
      Dim thisCommand As New SqlCommand(sql, thisConnection)
      Try
         thisConnection.Open()
         Console.WriteLine("Connection Opened")
         Dim thisReader As SqlDataReader = thisCommand.ExecuteReader()
         Dim schema As DataTable = thisReader.GetSchemaTable()
         For Each row As DataRow In schema.Rows
            For Each col As DataColumn In schema.Columns
               Console.WriteLine(col.ColumnName & " = " & row(col).ToString())
            Next
         Next
         thisReader.Close()
      Catch ex As SqlException
         Console.WriteLine("Error: " & ex.ToString())
      Finally
         thisConnection.Close()
         Console.WriteLine("Connection Closed")
      End Try
   End Sub
End Class

DataTable.Columns.Add

  
Imports System.Data
Imports System.Data.OleDb
Imports System.Windows.Forms
public class BindDataTableToControl
   public Shared Sub Main
        Application.Run(New Form1)
   End Sub
End class

Public Class Form1
    " The data source.
    Private m_ContactsTable As DataTable
    " The data source"s CurrencyManager.
    Private m_CurrencyManager As CurrencyManager
    Private Sub Form1_Load(ByVal sender As System.Object, _
     ByVal e As System.EventArgs) Handles MyBase.Load
        " Make a DataTable.
        m_ContactsTable = New DataTable("Contacts")
        " Add columns.
        m_ContactsTable.Columns.Add("FirstName", GetType(String))
        m_ContactsTable.Columns.Add("LastName", GetType(String))
        m_ContactsTable.Columns.Add("Street", GetType(String))
        m_ContactsTable.Columns.Add("City", GetType(String))
        m_ContactsTable.Columns.Add("State", GetType(String))
        m_ContactsTable.Columns.Add("Zip", GetType(String))
        " Make the combined FirstName/LastName unique.
        Dim first_last_columns() As DataColumn = { _
            m_ContactsTable.Columns("FirstName"), _
            m_ContactsTable.Columns("LastName") _
        }
        m_ContactsTable.Constraints.Add( _
            New UniqueConstraint(first_last_columns))
        " Make some contact data.
        m_ContactsTable.Rows.Add(New Object() {"A", "B","C", "D", "E", "11111"})
        m_ContactsTable.Rows.Add(New Object() {"F", "G","H", "I", "J", "22222"})
        m_ContactsTable.Rows.Add(New Object() {"K", "L","M", "N", "O", "33333"})
        m_ContactsTable.Rows.Add(New Object() {"P", "Q","R", "S", "T", "44444"})
        m_ContactsTable.Rows.Add(New Object() {"U", "V","W", "X", "Y", "55555"})
        m_ContactsTable.Rows.Add(New Object() {"Z", "A","B", "C", "D", "66666"})
        m_ContactsTable.Rows.Add(New Object() {"E", "F","G", "H", "I", "77777"})
        m_ContactsTable.Rows.Add(New Object() {"J", "K","L", "M", "N", "88888"})
        " Bind to controls.
        txtFirstName.DataBindings.Add("Text", m_ContactsTable, "FirstName")
        txtLastName.DataBindings.Add("Text", m_ContactsTable, "LastName")
        txtStreet.DataBindings.Add("Text", m_ContactsTable, "Street")
        txtCity.DataBindings.Add("Text", m_ContactsTable, "City")
        txtState.DataBindings.Add("Text", m_ContactsTable, "State")
        txtZip.DataBindings.Add("Text", m_ContactsTable, "Zip")
        " Save a reference to the CurrencyManager.
        m_CurrencyManager = _
            DirectCast(Me.BindingContext(m_ContactsTable), CurrencyManager)
    End Sub
    Private Sub btnFirst_Click(ByVal sender As System.Object, _
     ByVal e As System.EventArgs) Handles btnFirst.Click
        m_CurrencyManager.Position = 0
    End Sub
    Private Sub btnPrev_Click(ByVal sender As System.Object, _
     ByVal e As System.EventArgs) Handles btnPrev.Click
        m_CurrencyManager.Position -= 1
    End Sub
    Private Sub btnNext_Click(ByVal sender As System.Object, _
     ByVal e As System.EventArgs) Handles btnNext.Click
        m_CurrencyManager.Position += 1
    End Sub
    Private Sub btnLast_Click(ByVal sender As System.Object, _
     ByVal e As System.EventArgs) Handles btnLast.Click
        m_CurrencyManager.Position = m_CurrencyManager.Count - 1
    End Sub
    " Add a new record.
    Private Sub btnAdd_Click(ByVal sender As System.Object, _
     ByVal e As System.EventArgs) Handles btnAdd.Click
        m_CurrencyManager.AddNew()
    End Sub
    Private Sub btnDelete_Click(ByVal sender As System.Object, _
     ByVal e As System.EventArgs) Handles btnDelete.Click
        If MsgBox("Are you sure you want to delete this record?", _
            MsgBoxStyle.Question Or MsgBoxStyle.YesNo, _
            "Confirm Delete?") = MsgBoxResult.Yes _
        Then
            m_CurrencyManager.RemoveAt(m_CurrencyManager.Position)
        End If
    End Sub
End Class
<Global.Microsoft.VisualBasic.rupilerServices.DesignerGenerated()> _
Partial Public Class Form1
    Inherits System.Windows.Forms.Form
    "Form overrides dispose to clean up the component list.
    <System.Diagnostics.DebuggerNonUserCode()> _
    Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean)
        If disposing AndAlso components IsNot Nothing Then
            components.Dispose()
        End If
        MyBase.Dispose(disposing)
    End Sub
    "Required by the Windows Form Designer
    Private components As System.ruponentModel.IContainer
    "NOTE: The following procedure is required by the Windows Form Designer
    "It can be modified using the Windows Form Designer.  
    "Do not modify it using the code editor.
    <System.Diagnostics.DebuggerStepThrough()> _
    Private Sub InitializeComponent()
        Me.Label6 = New System.Windows.Forms.Label
        Me.Label5 = New System.Windows.Forms.Label
        Me.Label4 = New System.Windows.Forms.Label
        Me.Label3 = New System.Windows.Forms.Label
        Me.Label2 = New System.Windows.Forms.Label
        Me.Label1 = New System.Windows.Forms.Label
        Me.btnDelete = New System.Windows.Forms.Button
        Me.btnAdd = New System.Windows.Forms.Button
        Me.btnLast = New System.Windows.Forms.Button
        Me.btnNext = New System.Windows.Forms.Button
        Me.btnPrev = New System.Windows.Forms.Button
        Me.btnFirst = New System.Windows.Forms.Button
        Me.txtZip = New System.Windows.Forms.TextBox
        Me.txtState = New System.Windows.Forms.TextBox
        Me.txtCity = New System.Windows.Forms.TextBox
        Me.txtStreet = New System.Windows.Forms.TextBox
        Me.txtLastName = New System.Windows.Forms.TextBox
        Me.txtFirstName = New System.Windows.Forms.TextBox
        Me.SuspendLayout()
        "
        "Label6
        "
        Me.Label6.AutoSize = True
        Me.Label6.Location = New System.Drawing.Point(176, 104)
        Me.Label6.Name = "Label6"
        Me.Label6.Size = New System.Drawing.Size(22, 13)
        Me.Label6.TabIndex = 35
        Me.Label6.Text = "Zip"
        "
        "Label5
        "
        Me.Label5.AutoSize = True
        Me.Label5.Location = New System.Drawing.Point(8, 104)
        Me.Label5.Name = "Label5"
        Me.Label5.Size = New System.Drawing.Size(32, 13)
        Me.Label5.TabIndex = 34
        Me.Label5.Text = "State"
        "
        "Label4
        "
        Me.Label4.AutoSize = True
        Me.Label4.Location = New System.Drawing.Point(8, 80)
        Me.Label4.Name = "Label4"
        Me.Label4.Size = New System.Drawing.Size(24, 13)
        Me.Label4.TabIndex = 33
        Me.Label4.Text = "City"
        "
        "Label3
        "
        Me.Label3.AutoSize = True
        Me.Label3.Location = New System.Drawing.Point(8, 56)
        Me.Label3.Name = "Label3"
        Me.Label3.Size = New System.Drawing.Size(35, 13)
        Me.Label3.TabIndex = 32
        Me.Label3.Text = "Street"
        "
        "Label2
        "
        Me.Label2.AutoSize = True
        Me.Label2.Location = New System.Drawing.Point(8, 32)
        Me.Label2.Name = "Label2"
        Me.Label2.Size = New System.Drawing.Size(58, 13)
        Me.Label2.TabIndex = 31
        Me.Label2.Text = "Last Name"
        "
        "Label1
        "
        Me.Label1.AutoSize = True
        Me.Label1.Location = New System.Drawing.Point(8, 8)
        Me.Label1.Name = "Label1"
        Me.Label1.Size = New System.Drawing.Size(57, 13)
        Me.Label1.TabIndex = 30
        Me.Label1.Text = "First Name"
        "
        "btnDelete
        "
        Me.btnDelete.Location = New System.Drawing.Point(240, 144)
        Me.btnDelete.Name = "btnDelete"
        Me.btnDelete.Size = New System.Drawing.Size(32, 24)
        Me.btnDelete.TabIndex = 29
        Me.btnDelete.Text = "X"
        "
        "btnAdd
        "
        Me.btnAdd.Location = New System.Drawing.Point(200, 144)
        Me.btnAdd.Name = "btnAdd"
        Me.btnAdd.Size = New System.Drawing.Size(32, 24)
        Me.btnAdd.TabIndex = 28
        Me.btnAdd.Text = "+"
        "
        "btnLast
        "
        Me.btnLast.Location = New System.Drawing.Point(104, 144)
        Me.btnLast.Name = "btnLast"
        Me.btnLast.Size = New System.Drawing.Size(32, 24)
        Me.btnLast.TabIndex = 27
        Me.btnLast.Text = ">>"
        "
        "btnNext
        "
        Me.btnNext.Location = New System.Drawing.Point(72, 144)
        Me.btnNext.Name = "btnNext"
        Me.btnNext.Size = New System.Drawing.Size(32, 24)
        Me.btnNext.TabIndex = 26
        Me.btnNext.Text = ">"
        "
        "btnPrev
        "
        Me.btnPrev.Location = New System.Drawing.Point(40, 144)
        Me.btnPrev.Name = "btnPrev"
        Me.btnPrev.Size = New System.Drawing.Size(32, 24)
        Me.btnPrev.TabIndex = 25
        Me.btnPrev.Text = "<"
        "
        "btnFirst
        "
        Me.btnFirst.Location = New System.Drawing.Point(8, 144)
        Me.btnFirst.Name = "btnFirst"
        Me.btnFirst.Size = New System.Drawing.Size(32, 24)
        Me.btnFirst.TabIndex = 24
        Me.btnFirst.Text = "<<"
        "
        "txtZip
        "
        Me.txtZip.Anchor = CType(((System.Windows.Forms.AnchorStyles.Top Or System.Windows.Forms.AnchorStyles.Left) _
                    Or System.Windows.Forms.AnchorStyles.Right), System.Windows.Forms.AnchorStyles)
        Me.txtZip.Location = New System.Drawing.Point(200, 104)
        Me.txtZip.Name = "txtZip"
        Me.txtZip.Size = New System.Drawing.Size(72, 20)
        Me.txtZip.TabIndex = 23
        "
        "txtState
        "
        Me.txtState.Location = New System.Drawing.Point(72, 104)
        Me.txtState.Name = "txtState"
        Me.txtState.Size = New System.Drawing.Size(32, 20)
        Me.txtState.TabIndex = 22
        "
        "txtCity
        "
        Me.txtCity.Anchor = CType(((System.Windows.Forms.AnchorStyles.Top Or System.Windows.Forms.AnchorStyles.Left) _
                    Or System.Windows.Forms.AnchorStyles.Right), System.Windows.Forms.AnchorStyles)
        Me.txtCity.Location = New System.Drawing.Point(72, 80)
        Me.txtCity.Name = "txtCity"
        Me.txtCity.Size = New System.Drawing.Size(200, 20)
        Me.txtCity.TabIndex = 21
        "
        "txtStreet
        "
        Me.txtStreet.Anchor = CType(((System.Windows.Forms.AnchorStyles.Top Or System.Windows.Forms.AnchorStyles.Left) _
                    Or System.Windows.Forms.AnchorStyles.Right), System.Windows.Forms.AnchorStyles)
        Me.txtStreet.Location = New System.Drawing.Point(72, 56)
        Me.txtStreet.Name = "txtStreet"
        Me.txtStreet.Size = New System.Drawing.Size(200, 20)
        Me.txtStreet.TabIndex = 20
        "
        "txtLastName
        "
        Me.txtLastName.Anchor = CType(((System.Windows.Forms.AnchorStyles.Top Or System.Windows.Forms.AnchorStyles.Left) _
                    Or System.Windows.Forms.AnchorStyles.Right), System.Windows.Forms.AnchorStyles)
        Me.txtLastName.Location = New System.Drawing.Point(72, 32)
        Me.txtLastName.Name = "txtLastName"
        Me.txtLastName.Size = New System.Drawing.Size(200, 20)
        Me.txtLastName.TabIndex = 19
        "
        "txtFirstName
        "
        Me.txtFirstName.Anchor = CType(((System.Windows.Forms.AnchorStyles.Top Or System.Windows.Forms.AnchorStyles.Left) _
                    Or System.Windows.Forms.AnchorStyles.Right), System.Windows.Forms.AnchorStyles)
        Me.txtFirstName.Location = New System.Drawing.Point(72, 8)
        Me.txtFirstName.Name = "txtFirstName"
        Me.txtFirstName.Size = New System.Drawing.Size(200, 20)
        Me.txtFirstName.TabIndex = 18
        "
        "Form1
        "
        Me.AutoScaleDimensions = New System.Drawing.SizeF(6.0!, 13.0!)
        Me.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font
        Me.ClientSize = New System.Drawing.Size(278, 175)
        Me.Controls.Add(Me.Label6)
        Me.Controls.Add(Me.Label5)
        Me.Controls.Add(Me.Label4)
        Me.Controls.Add(Me.Label3)
        Me.Controls.Add(Me.Label2)
        Me.Controls.Add(Me.Label1)
        Me.Controls.Add(Me.btnDelete)
        Me.Controls.Add(Me.btnAdd)
        Me.Controls.Add(Me.btnLast)
        Me.Controls.Add(Me.btnNext)
        Me.Controls.Add(Me.btnPrev)
        Me.Controls.Add(Me.btnFirst)
        Me.Controls.Add(Me.txtZip)
        Me.Controls.Add(Me.txtState)
        Me.Controls.Add(Me.txtCity)
        Me.Controls.Add(Me.txtStreet)
        Me.Controls.Add(Me.txtLastName)
        Me.Controls.Add(Me.txtFirstName)
        Me.Name = "Form1"
        Me.Text = "UseCurrencyManager"
        Me.ResumeLayout(False)
        Me.PerformLayout()
    End Sub
    Friend WithEvents Label6 As System.Windows.Forms.Label
    Friend WithEvents Label5 As System.Windows.Forms.Label
    Friend WithEvents Label4 As System.Windows.Forms.Label
    Friend WithEvents Label3 As System.Windows.Forms.Label
    Friend WithEvents Label2 As System.Windows.Forms.Label
    Friend WithEvents Label1 As System.Windows.Forms.Label
    Friend WithEvents btnDelete As System.Windows.Forms.Button
    Friend WithEvents btnAdd As System.Windows.Forms.Button
    Friend WithEvents btnLast As System.Windows.Forms.Button
    Friend WithEvents btnNext As System.Windows.Forms.Button
    Friend WithEvents btnPrev As System.Windows.Forms.Button
    Friend WithEvents btnFirst As System.Windows.Forms.Button
    Friend WithEvents txtZip As System.Windows.Forms.TextBox
    Friend WithEvents txtState As System.Windows.Forms.TextBox
    Friend WithEvents txtCity As System.Windows.Forms.TextBox
    Friend WithEvents txtStreet As System.Windows.Forms.TextBox
    Friend WithEvents txtLastName As System.Windows.Forms.TextBox
    Friend WithEvents txtFirstName As System.Windows.Forms.TextBox
End Class

DataTable.Rows

  

Imports System
Imports System.Data
Imports System.Data.OleDb
Imports System.Data.SqlClient
Imports System.Collections
Imports System.Windows.Forms
Imports System.Resources
Public Class MainClass
    Shared Sub Main()
        Dim strConnectionString As String = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=Employee.mdb;"
        Dim objConnection As New OleDbConnection(strConnectionString)
        Dim strSQL As String = "SELECT FirstName, LastName FROM Employee"
        Dim objCommand As New OleDbCommand(strSQL, objConnection)
        Dim objDataAdapter As New OleDbDataAdapter(objCommand)
        Dim objDataTable As New Data.DataTable("Employee")
        Dim objDataRow As DataRow
        Try
            objConnection.Open()
            objDataAdapter.Fill(objDataTable)
            For Each objDataRow In objDataTable.Rows
                Console.WriteLine(objDataRow.Item("FirstName") & " " & objDataRow.Item("LastName"))
            Next
        Catch OleDbExceptionErr As OleDbException
            Console.WriteLine(OleDbExceptionErr.Message)
        Catch InvalidOperationExceptionErr As InvalidOperationException
            Console.WriteLine(InvalidOperationExceptionErr.Message)
        End Try
        objConnection.Close()
        objDataRow = Nothing
        objDataTable.Dispose()
        objDataTable = Nothing
        objDataAdapter.Dispose()
        objDataAdapter = Nothing
        objCommand.Dispose()
        objCommand = Nothing
        objConnection.Dispose()
        objConnection = Nothing
    End Sub
End Class

DataTable.Rows.Add

  
Imports System
Imports System.Data
Imports System.Data.SqlClient

public class MainClass
   Shared Sub Main()
      Dim thisConnection As New SqlConnection("server=(local)\SQLEXPRESS;" & _
          "integrated security=sspi;database=MyDatabase")
      " Sql Query 
      Dim sql As String = "SELECT * FROM Employee"
      Try
         " Create Data Adapter
         Dim da As New SqlDataAdapter
         da.SelectCommand = New SqlCommand(sql, thisConnection)
         " Create and fill Dataset
         Dim ds As New DataSet
         da.Fill(ds, "Employee")
         " Get the Data Table
         Dim dt As DataTable = ds.Tables("Employee")
         " Display Rows Before Changed
         Console.WriteLine("Before altering the dataset")
         For Each row As DataRow In dt.Rows
            Console.WriteLine("{0} | {1} | {2}", _
               row("ID").ToString().PadRight(10), _
               row("FirstName").ToString().PadRight(10), _
               row("LastName"))
         Next
         dt.Columns("FirstName").AllowDBNull = True
         dt.Rows(0)("FirstName") = "Birm"
         Dim newRow As DataRow = dt.NewRow()
         newRow("ID") = "99"
         newRow("FirstName") = "Ever"
         newRow("LastName") = "Dame"
         dt.Rows.Add(newRow)

         For Each row As DataRow In dt.Rows
            Console.WriteLine("{0} | {1} | {2}", _
               row("ID").ToString().PadRight(10), _
               row("FirstName").ToString().PadRight(10), _
               row("LastName"))
         Next
      Catch ex As SqlException
         Console.WriteLine("Error: " & ex.ToString())
      Finally
         thisConnection.Close()
         Console.WriteLine("Connection Closed")
      End Try
   End Sub
End Class