Export to Excel using Developer Express

Private Sub btnExportarExcel_Click(sender As Object, e As EventArgs) Handles btnExportarExcel.Click
        Me.GridView1.ExportToXls("linq.xls")
        Process.Start("linq.xls")
    End Sub

Aggregate Functions in LinQ

' CONSULTA QUE UTILIZA FUNCIONES AGREGADAS
        Dim tblinvoices As List(Of Invoice) = InvoiceDB.GetInvoices
        Dim tbllinq = Aggregate invoice In tblinvoices
                      Where invoice.InvoiceDate > #1/1/2010#
                      Into Average(invoice.InvoiceTotal),
                      Sum(invoice.InvoiceTotal)

        'MsgBox("Promedio = " & tbllinq.Average & "; Suma = " & tbllinq.Sum)
        MsgBox(tbllinq.ToString())

Join in LinQ

' Consulta que utiliza join entre dos tablas
        Me.GridView1.Columns.Clear()
        Dim tblinvoices As List(Of Invoice) = InvoiceDB.GetInvoices
        Dim tblvendedor As List(Of Vendor) = VendorDB.GetVendors

        Dim tbllinq = From invoices In tblinvoices
                      Join vendedor In tblvendedor
                      On invoices.VendorID Equals vendedor.VendorID
                      Where invoices.InvoiceTotal > 3000
                      Order By vendedor.Name
                      Select invoices.InvoiceNumber,
                            invoices.InvoiceDate,
                            invoices.InvoiceTotal,
                            vendedor.Name,
                            vendedor.State

        gvEjemplo.DataSource = tbllinq.ToList

Date example in LinQ

Dim tblinvoices As List(Of Invoice) = InvoiceDB.GetInvoices
        Dim tbllinq = From invoices In tblinvoices
                      Where invoices.InvoiceDate >= #12/1/2009# And
                        invoices.InvoiceDate <= #5/31/2010#
                    Select invoices.InvoiceNumber,
                        invoices.InvoiceDate,
                        invoices.InvoiceTotal

        Me.gvEjemplo.DataSource = tbllinq.ToList

Select in LinQ

Private Sub btnEjemplo7_Click(sender As Object, e As EventArgs) Handles btnEjemplo7.Click
        ' Consulta en linq que regresa de facturas mayores 2000
        Dim tblinvoices As List(Of Invoice) = InvoiceDB.GetInvoices
        Dim tbllinq = From invoices In tblinvoices
                      Where invoices.InvoiceTotal > 2000
                      Order By invoices.InvoiceDate Descending
                      Select invoices.InvoiceNumber,
                        invoices.InvoiceTotal,
                        invoices.InvoiceDate

        Me.gvEjemplo.DataSource = tbllinq.ToList
    End Sub

Get SQL data using LinQ Connection

Imports System.Data.SqlClient

Public Class InvoiceDB

    Public Shared Function GetInvoices() _
            As List(Of Invoice)
        Dim invoiceList As New List(Of Invoice)
        Dim connection As SqlConnection = LinqDB.GetConnection
        Dim selectstatement As String =
            "SELECT InvoiceID, VendorID, InvoiceNumber, InvoiceDate, InvoiceTotal, " &
            "PaymentTotal, CreditTotal, TermsID, DueDate, PaymentDate " &
            "FROM Invoices " &
            "ORDER BY InvoiceDate"
        Dim selectCommand As New SqlCommand(selectstatement, connection)
        Try
            connection.Open()
            Dim reader As SqlDataReader = selectCommand.ExecuteReader()
            Dim invoice As Invoice
            Do While reader.Read
                invoice = New Invoice
                invoice.InvoiceID = CInt(reader("InvoiceID"))
                invoice.VendorID = CInt(reader("VendorID"))
                invoice.InvoiceNumber = reader("InvoiceNumber").ToString
                invoice.InvoiceDate = CDate(reader("InvoiceDate"))
                invoice.InvoiceTotal = CDec(reader("InvoiceTotal"))
                invoice.PaymentTotal = CDec(reader("PaymentTotal"))
                invoice.CreditTotal = CDec(reader("CreditTotal"))
                invoice.TermsID = CDec(reader("TermsID"))
                invoice.DueDate = CDate(reader("DueDate"))
                If IsDBNull(reader("PaymentDate")) Then
                    invoice.PaymentDate = Nothing
                Else
                    invoice.PaymentDate = CDate(reader("PaymentDate"))
                End If
                invoiceList.Add(invoice)
            Loop
            reader.Close()
        Catch ex As SqlException
            Throw ex
        Finally
            connection.Close()
        End Try
        Return invoiceList
    End Function

End Class

Class example in Visual Studio

Public Class Invoice
    Private m_InvoiceID As Integer
    Private m_VendorID As Integer
    Private m_InvoiceNumber As String
    Private m_InvoiceDate As Date
    Private m_InvoiceTotal As Decimal
    Private m_PaymentTotal As Decimal
    Private m_CreditTotal As Decimal
    Private m_TermsID As Integer
    Private m_DueDate As Date
    Private m_PaymentDate As Nullable(Of Date)

    Public Sub New()

    End Sub

    Public Property InvoiceID() As Integer
        Get
            Return m_InvoiceID
        End Get
        Set(ByVal value As Integer)
            m_InvoiceID = value
        End Set
    End Property

    Public Property VendorID() As Integer
        Get
            Return m_VendorID
        End Get
        Set(ByVal value As Integer)
            m_VendorID = value
        End Set
    End Property

    Public Property InvoiceNumber() As String
        Get
            Return m_InvoiceNumber
        End Get
        Set(ByVal value As String)
            m_InvoiceNumber = value
        End Set
    End Property

    Public Property InvoiceDate() As Date
        Get
            Return m_InvoiceDate
        End Get
        Set(ByVal value As Date)
            m_InvoiceDate = value
        End Set
    End Property

    Public Property InvoiceTotal() As Decimal
        Get
            Return m_InvoiceTotal
        End Get
        Set(ByVal value As Decimal)
            m_InvoiceTotal = value
        End Set
    End Property

    Public Property PaymentTotal() As Decimal
        Get
            Return m_PaymentTotal
        End Get
        Set(ByVal value As Decimal)
            m_PaymentTotal = value
        End Set
    End Property

    Public Property CreditTotal() As Decimal
        Get
            Return m_CreditTotal
        End Get
        Set(ByVal value As Decimal)
            m_CreditTotal = value
        End Set
    End Property

    Public Property TermsID() As Integer
        Get
            Return m_TermsID
        End Get
        Set(ByVal value As Integer)
            m_TermsID = value
        End Set
    End Property

    Public Property DueDate() As Date
        Get
            Return m_DueDate
        End Get
        Set(ByVal value As Date)
            m_DueDate = value
        End Set
    End Property

    Public Property PaymentDate() As Nullable(Of Date)
        Get
            If m_PaymentDate.HasValue Then
                Return CDate(m_PaymentDate)
            Else
                Return Nothing
            End If
        End Get
        Set(ByVal value As Nullable(Of Date))
            m_PaymentDate = value
        End Set
    End Property

    Public ReadOnly Property BalanceDue() As Decimal
        Get
            Return m_InvoiceTotal - m_PaymentTotal - m_CreditTotal
        End Get
    End Property

End Class

Average in LinQ

Private Sub btnEjemplo4_Click(sender As Object, e As EventArgs) Handles btnEjemplo4.Click
        Dim numeros() As Integer = {2, 4, 6, 8, 10}
        Dim tbllinq = numeros.Average
        Me.gvEjemplo.DataSource = tbllinq.ToString
    End Sub

String SQL Query in LinQ

Private Sub btnEjemplo3_Click(sender As Object, e As EventArgs) Handles btnEjemplo3.Click
        Dim resultado As String
        Dim animales() As String = {"perro", "gato", "raton", "jirafa", "gallina"}
        Dim tbllinq = From v In animales
                      Where v.ToUpper Like "G*"
        'Where v.ToUpper.Contains("G")

        Me.gvEjemplo.DataSource = tbllinq.ToList
    End Sub

Where and Order Commands in LinQ

Private Sub btnEjemplo1_Click(sender As Object, e As EventArgs) Handles btnEjemplo1.Click
        ' Consulta a arreglo de numeros
        Dim resultado As String
        Dim values() As Integer = {1, 10, 100, 5}
        Dim tbllinq = From v In values
        'Where v > 10

        'Dim values() As Integer = {3, 10, -1, 30, -3}
        'Dim tbllinq = From v In values
        '              Order By v Descending

        Me.gvEjemplo.DataSource = tbllinq.ToList
    End Sub

LinQ in Visual Studio 2013

1) Insertar un Layout Control

2) Insertar LabelControl y SimpleButton

3) Insertar un DataGridView

4) Abrir un evento para el boton "Ejemplo1"

5) Copiar el siguiente codigo

Public Class frmLinQ

    Private Sub btnEjemplo1_Click(sender As Object, e As EventArgs) Handles btnEjemplo1.Click

        ' Consulta a arreglo de numeros

        Dim resultado As String

        Dim values() As Integer = {1, 10, 100, 5}

        Dim tbllinq = From v In values

        

        Me.gvEjemplo.DataSource = tbllinq.ToList

    End Sub

End Class

6) Ejecutar el proyecto

Change color theme in Visual Studio 2013

1) Clic in the menu "Tools > Options"

2) In Enviroment > General, select your favourite color theme "Blue", "Dark" and "Light"

Get Current Selected Row

private void dgvTabla_CellContentClick(object sender, DataGridViewCellEventArgs e)

        {

            int fila;

            fila = this.dgvTabla.CurrentCell.RowIndex;

            MessageBox.Show(fila.ToString());

        }

Select a C# Form for run it

Para seleccionar un determinado formulario C# y correrlo, abrimos del Proyecto la clase "Program.cs" y establecemos el nombre del formulario que deseamos inicie al presionar el botón "Run"

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace WindowsFormsApplication1
{
    static class Program
    {
        /// <summary>
        /// The main entry point for the application.
        /// </summary>
        [STAThread]
        static void Main()
        {
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);
            Application.Run(new frmMiFormulario());
        }
    }
}

El nombre del formulario lo obtenemos del código fuente del mismo

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace WindowsFormsApplication1
{
    public partial class frmMiFormulario: Form
    {
        public frmMiFormulario()
        {
            InitializeComponent();
        }

...