Chuletas .Net /*Pequeños conceptos y tips para desarrollar en .Net*/

ChuletasDotNet.cs

//------------------------------ concatenar en el eval
<asp:Image ID="Image1" runat="server" ImageUrl='<%# "~/styles/images/" + Eval("value") + ".png"%>'
 ToolTip='<%# Convert.ToDateTime(Eval("value")).ToString("dddd d, MMMM yyyy -- HH:mm:ss") %>' />

ImageUrl='<%# "~/fixed/showimage.aspx?img=" + Eval("im_image")%>'
ImageUrl='<%# Eval("im_image","~/fixed/showimage.aspx?img={0}")%>'

//----------------------------------- para dormir el proceso
Thread.Sleep(300); //en milisegundos

//----------------------------------- Acceder a la cadena de conexion en el webConfig
string OraString = ConfigurationManager.ConnectionStrings["C"].ConnectionString;

//----------------------------------- Condicional en una sola linea
string = bool ? string.empty : cadena
string = (cadena == string.empty) ? "Valor vacio" : cadena
el ? se puede considerar como el if
el : se puede considerar como el else

//----------------------------------- Para sustraer caracteres a un string
string saludo = "Hola Mundo";
saludo.Replace("Mundo","Infirno");
saludo.Remove(1) // quita el segundo caracter.

//----------------------------------- Subir un archivo 
HttpFileCollection archivos = Request.Files;
            for (int i = 0; i <= archivos.Count - 1; i++)
            {
                HttpPostedFile postedFile = archivos[i];
                if (postedFile.ContentLength > 0)
                {
                    postedFile.SaveAs(Server.MapPath(@"uploads\") + Path.GetFileName(postedFile.FileName));
                    lblMsg.Text = "Archivos subidos correctamente.";
                }
            }

//---------------------------------- Server.Map para saber la ruta de nuestros archivos en asp.net
<%
response.write(Server.MapPath("test.asp") & "<br />")
response.write(Server.MapPath("script/test.asp") & "<br />")
response.write(Server.MapPath("/script/test.asp") & "<br />")
response.write(Server.MapPath("\script") & "<br />")
response.write(Server.MapPath("/") & "<br />")
response.write(Server.MapPath("\") & "<br />")
%>

//---------- cada consulta anterioro imprime lo siguiente
c:\inetpub\wwwroot\script\test.asp
c:\inetpub\wwwroot\script\script\test.asp
c:\inetpub\wwwroot\script\test.asp
c:\inetpub\wwwroot\script
c:\inetpub\wwwroot
c:\inetpub\wwwroot

HttpContext.Current.Server.MapPath("/")

//------------------------ Obtener archivos de un fichero ver System.IO
DirectoryInfo ListaArchivos = new DirectoryInfo(Server.MapPath("/") + rutaImgDocuments );
foreach (FileInfo archivo in ListaArchivos.GetFiles("*")
     archivo.name

//------------Definir una lista de strings
List<string> Listadestrings = new List<string();
Listadestrings.Add("primero");
Listadestrings.Add("segundo");
Listadestrings.Add("tercero");

//-------------Para calcular la diferencia entre dos horas. 
DateTime startTime = DateTime.Now;
DateTime endTime = DateTime.Now.AddSeconds( 75 );
 
TimeSpan span = endTime.Subtract ( startTime );
Console.WriteLine( "Time Difference (seconds): " + span.Seconds );
Console.WriteLine( "Time Difference (minutes): " + span.Minutes );
Console.WriteLine( "Time Difference (hours): " + span.Hours );
Console.WriteLine( "Time Difference (days): " + span.Days );

//-------------para colocar el cursor en modod de espera se utiliza 
Cursor.Current = Cursors.WaitCursor;
Cursor.Current = Cursors.Default;

//-------------Para establecer la pagina de inicio predeterminada en ASP.Net
<system.webServer>
        <defaultDocument>
            <files>
                <add value="MyDefaultPage.aspx" />
            </files>
        </defaultDocument>
    </system.webServer>

//------------ Usando la cadena de conexion 

string cadenaConexion = @"server=(local)\PRODUCCION; database=BDPolizas; user id=sa; password=password; Trusted_Connection=False; timeout = 60 ";

            using (SqlConnection con = new SqlConnection(cadenaConexion))
            {
                try
                {
                    con.Open();
                    Console.WriteLine("CONEXION EXITOSA");
                }
                catch (Exception error)
                {
                    Console.WriteLine(error.Message);
                    Console.ReadKey();                   
                }
                finally {
                    con.Close();
                }
            }

DataSet DSCitas = new DataSet();
            using (SqlConnection conn = new SqlConnection(ConnStringDataBase))
            {
                try
                {
                    string sqltext = "SELECT * FROM CITAS";
                    SqlDataAdapter dAdapter = new SqlDataAdapter(sqltext, conn);
                    dAdapter.Fill(DSCitas);
                    return DSCitas;

// -------------- Utilizando Parametros en URL

response.redirect("a.aspx?ids=1&val=100",true)
a=Request.QueryString("ids") 
b= Request.QueryString("val")
a = 1
b = 100

//----------------- CONSULTA ORACLE 

    string connStr = ConfigurationManager .ConnectionStrings["connString"].ConnectionString;
    OracleConnection OraCon = null ;
    OracleCommand OraComm = null ;
    OracleDataAdapter OraDataAdapter = null ;
    DataSet data = null;
        
    public DataSet GetStoreInfo()
    {
        using (OraCon = new OracleConnection(connStr))
        {
            using (OraComm = new OracleCommand( "MY.PROCEDURE" , OraCon))
            {
                data = new DataSet ();
                try
                {
                    OraCon.Open();

                    OraComm.CommandType = CommandType .StoredProcedure;
                    OraComm.Parameters.Add( "OUTCURSOR" , OracleDbType .RefCursor).Direction = ParameterDirection .Output;

                    OraDataAdapter = new OracleDataAdapter (OraComm);
                    OraDataAdapter.TableMappings.Add( "INFO" , "OUTCURSOR" );
                    OraDataAdapter.Fill(data);
                }
                catch (OracleException errorOra)
                {
                    throw new Exception( "Oracle error - " + errorOra.Message + errorOra.ToString(), errorOra.InnerException);
                }
                catch (Exception erroSys)
                {
                    throw new Exception( "Oracle error - " + erroSys.Message + erroSys.ToString(), erroSys.InnerException);
                }
            }
        }
        return data;
    }
//------------- Retornar la sesion en una clase statica

System.Web.SessionState.HttpSessionState sessions = HttpContext.Current.Session;
String _mySession = sessions[ Constants.NameSessionUser];

//-------------- Para verificar que un archivo existe en asp.net
archivo = file.txt example
if (File .Exists(Server.MapPath("~/"+ archivo)))
                    using ( StreamReader reader = new StreamReader(Server.MapPath("~/" + archivo)))
                        while (reader.Peek() >= 0)
                            HTML += reader.ReadLine();

//----------------- Export DataTable to excel.

public static void ExportDataTableToExcel( string fileName, DataTable _datatable)
{
    String style = @"<style> .textmode { mso-number-format:\@; } </script> ";
    HttpContext.Current.Response.Clear();
    HttpContext.Current.Response.AddHeader(
        "content-disposition", string .Format("attachment; filename={0}" , fileName));
    HttpContext.Current.Response.ContentType = "application/ms-excel" ;
    using ( StringWriter sw = new StringWriter ())
    {
        using ( HtmlTextWriter htw = new HtmlTextWriter (sw))
        {
            //  Create a form to contain the grid
            Table table = new Table();                   
             for ( int i = 0; i < _datatable.Rows.Count; i++)
            {
                TableRow row = new TableRow();
                for ( int j = 0; j < _datatable.Columns.Count; j++)
                {
                    TableCell cell = new TableCell();
                    cell.Text = _datatable.Rows[i][j].ToString();
                    row.Cells.Add(cell);
                }
                // Add the TableRow to the Table
                table.Rows.Add(row);
            }
            table.RenderControl(htw);
             /// Type text
            HttpContext.Current.Response.Write(style);
            //  render the htmlwriter into the response
            HttpContext.Current.Response.Write(sw.ToString());
            HttpContext.Current.Response.End();
        }
    }
}

//------- Cargar un archivo XML en una lista o entidad. 

            customerList = (
                from e in XDocument.Load( "MyFile.xml").
                          Root.Elements( "customer")
                select new Customer
                {
                    CustomerID = ( string)e.Element( "id"),
                    CompanyName = ( string)e.Element( "name"),
                    Address = ( string)e.Element( "address"),
                    City = ( string)e.Element( "city"),
                    Region = ( string)e.Element( "region"),
                    PostalCode = ( string)e.Element( "postalcode"),
                    Country = ( string)e.Element( "country"),
                    Phone = ( string)e.Element( "phone"),
                    Fax = ( string)e.Element( "fax"),
                    Orders = (
                        from o in e.Elements( "orders").Elements("order" )
                        select new Order
                        {
                            OrderID = ( int)o.Element( "id"),
                            OrderDate = ( DateTime)o.Element( "orderdate"),
                            Total = ( decimal)o.Element( "total")
                        })
                        .ToArray()
                })
                .ToList();

//--------------Exportat DataTable to excel in WPF
try
{  
    Microsoft.Office.Interop.Excel. Application excel = null ;
    Microsoft.Office.Interop.Excel. Workbook wb = null;

    object missing = Type.Missing;
    Microsoft.Office.Interop.Excel. Worksheet ws = null;
    Microsoft.Office.Interop.Excel. Range rng = null;

    try
    {
        excel = new Microsoft.Office.Interop.Excel. Application();
        wb = excel.Workbooks.Add();
        ws = (Microsoft.Office.Interop.Excel. Worksheet)wb.ActiveSheet;

        for ( int Idx = 0; Idx < dataToExcel.Columns.Count; Idx++)
        {
            ws.Range[ "A1"].Offset[0, Idx].Value = dataToExcel.Columns[Idx].ColumnName;
        }

        for ( int Idx = 0; Idx < dataToExcel.Rows.Count; Idx++)
        { 
            ws.Range[ "A2"].Offset[Idx].Resize[1, dataToExcel.Columns.Count].Value =
            dataToExcel.Rows[Idx].ItemArray;
        }

        excel.Visible = true;
        wb.Activate();
    }
    catch ( COMException ex)
    {
        MessageBox.Show("Error asignando el archivo Excel: " + ex.ToString());
    }
}
catch ( Exception ex)
{
    MessageBox.Show("Error: " + ex.ToString());
}

//----PAGINACION Y ORDENACION DE GRIDVIEWS
// PAGINACION Y ORDENACION

   SortDirection _sortDir;

protected void gvVentasByRegions_PageIndexChanging( object sender, GridViewPageEventArgs e)
{
    pageAndSort(gvVentasByRegions, GridViewSortExpresion, (DataTable)Session[_nameSessionData], e.NewPageIndex);
}

protected void pageAndSort( GridView gv, string sortField, DataTable dt, int iPage)
{
    _sortDir = GridViewSortDirection;
    Utilities.pageAndSort(gv, ref _sortDir, sortField, dt, iPage);
    GridViewSortDirection = _sortDir;
}

protected void gvVentasByRegions_Sorting( object sender, GridViewSortEventArgs e)
{
    GridViewSortExpresion = e.SortExpression;
    pageAndSort(gvVentasByRegions, GridViewSortExpresion, (DataTable)Session[_nameSessionData], gvVentasByRegions.PageIndex);
}

/// <summary>
/// Manejo de las direcciones de ordenacion en la grilla
/// </summary>
public SortDirection GridViewSortDirection
{
    get
    {
        if (ViewState[ "sortDirection"] == null )
            ViewState[ "sortDirection"] = SortDirection .Ascending;
        return ( SortDirection)ViewState["sortDirection" ];
    }
    set { ViewState[ "sortDirection"] = value ; }

}

/// <summary>
/// Manejo de los campos de ordenacion o exp. de ordenacion
/// </summary>
public string GridViewSortExpresion
{
    get
    {
        if (ViewState[ "sortExpresion"] == null )
            ViewState[ "sortExpresion"] = string .Empty;
        return ( string)ViewState[ "sortExpresion"];
    }
    set { ViewState[ "sortExpresion"] = value ; }

}

//----------- Default button para un control 

<asp:Panel runat="server" DefaultButton="Button1">
   <asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>    
   <asp:Button ID="Button1" runat="server" style="display:none" OnClick="Button1_Click" /></asp:Panel>
   
//----- Registrar codigo jquery o javascript desde el codebehind
  
  string script = "alert(' " + "Hola desde el code behind " + " ');" ;
  ScriptManager.RegisterStartupScript(updatePanel, Page.GetType(), "msg" , script, true );
  //Tener en cuenta registrar el id del updatepanel

//--------------redirect page 404 en el redirect at web.config

<customErrors mode="RemoteOnly" 
     defaultRedirect="~/error404.aspx">
    <error statusCode="404" redirect="~/error404.aspx"/>
</customErrors>