VB.Net/Database ADO.net/Table Schema — различия между версиями

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Текущая версия на 12:44, 26 мая 2010

Get data table schema form SqlDataReader

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
            Console.WriteLine("---------------")
         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


Use datagrid to display table schema

Imports System
Imports System.Collections
Imports System.Data
Imports System.IO
Imports System.Xml.Serialization
Imports System.Xml
Imports System.Windows.Forms
Imports System.Data.SqlClient

Public Class MainClass
    Shared Sub Main()
        Dim form1 As Form = New Form1
        Application.Run(form1)
    End Sub
End Class


Public Class Form1
    Inherits System.Windows.Forms.Form
#Region " Windows Form Designer generated code "
    Public Sub New()
        MyBase.New()
        "This call is required by the Windows Form Designer.
        InitializeComponent()
        "Add any initialization after the InitializeComponent() call
    End Sub
    "Form overrides dispose to clean up the component list.
    Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean)
        If disposing Then
            If Not (components Is Nothing) Then
                components.Dispose()
            End If
        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.
    Friend WithEvents Button1 As System.Windows.Forms.Button
    Friend WithEvents DataGrid1 As System.Windows.Forms.DataGrid
    <System.Diagnostics.DebuggerStepThrough()> Private Sub InitializeComponent()
        Me.Button1 = New System.Windows.Forms.Button()
        Me.DataGrid1 = New System.Windows.Forms.DataGrid()
        CType(Me.DataGrid1, System.ruponentModel.ISupportInitialize).BeginInit()
        Me.SuspendLayout()
        "
        "Button1
        "
        Me.Button1.Location = New System.Drawing.Point(648, 448)
        Me.Button1.Name = "Button1"
        Me.Button1.TabIndex = 3
        Me.Button1.Text = "Go"
        "
        "DataGrid1
        "
        Me.DataGrid1.DataMember = ""
        Me.DataGrid1.HeaderForeColor = System.Drawing.SystemColors.ControlText
        Me.DataGrid1.Location = New System.Drawing.Point(8, 8)
        Me.DataGrid1.Name = "DataGrid1"
        Me.DataGrid1.Size = New System.Drawing.Size(720, 432)
        Me.DataGrid1.TabIndex = 2
        "
        "Form1
        "
        Me.AutoScaleBaseSize = New System.Drawing.Size(6, 15)
        Me.ClientSize = New System.Drawing.Size(736, 480)
        Me.Controls.AddRange(New System.Windows.Forms.Control() {Me.Button1, Me.DataGrid1})
        Me.Name = "Form1"
        Me.Text = "Form1"
        CType(Me.DataGrid1, System.ruponentModel.ISupportInitialize).EndInit()
        Me.ResumeLayout(False)
    End Sub
#End Region
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Dim con As New SqlConnection( _
            "Server=(local)\SQLEXPRESS;Initial Catalog=MyDatabase;Integrated Security=SSPI")
        Dim cmd As New SqlCommand("SELECT * FROM Employee", con)
        Try
            con.Open()
            Dim reader As SqlDataReader = _
                                  cmd.ExecuteReader(CommandBehavior.SchemaOnly)
            DataGrid1.SetDataBinding(reader.GetSchemaTable(), "")
            reader.Close()
        Finally
            con.Close()
        End Try
    End Sub
End Class