// instantiate DataTableDataTable dTable = new DataTable("Dynamically_Generated");
// create columns for the DataTable DataColumn auto = new DataColumn("AutoID", typeof(System.Int32)); dTable.Columns.Add(auto); // create another column DataColumn name = new DataColumn("Name", typeof(string)); dTable.Columns.Add(name); // create one more column DataColumn address = new DataColumn("Address", typeof(string)); dTable.Columns.Add(address);
// specify it as auto increment field auto.AutoIncrement = true; auto.AutoIncrementSeed = 1; auto.ReadOnly = true;If you want a particular column to be a unique column ie. you don't want duplicate records into that column, then set its Unique property to true like below.
auto.Unique = true;
// create primary key on this fieldDataColumn[] pK = new DataColumn[1]; pK[0] = auto; dTable.PrimaryKey = pK;Till now we have created the DataTable, now lets populate the DataTable with some data.
// populate the DataTable using DataRow objectDataRow row = null; for (int i = 0; i < 5; i++) {Instead of using the column name, you can use ColumnIndex too, however it is not suggested as you might want to add a column in the mid of the table then you will need to change your code wherever you have specified the index of the column. Same applies while reading or writing values into Database column.row = dTable.NewRow(); row["AutoID"] = i + 1; row["Name"] = i + " - Ram"; row["Address"] = "Ram Nagar, India - " + i; dTable.Rows.Add(row);}
// manually adding rows using array of valuesdTable.Rows.Add(6, "Manual Data - 1", "Manual Address - 1, USA"); dTable.Rows.Add(7, "Manual Data - 2", "Manual Address - 2, USA");
// modify certain values into the DataTabledTable.Rows[2]["AutoID"] = 20; dTable.Rows[2]["Name"] = "Modified"; dTable.Rows[2]["Address"] = "Modified Address"; dTable.AcceptChanges();Deleting Row
// Delete rowdTable.Rows[1].Delete(); dTable.AcceptChanges();
DataRow[] rows = dTable.Select(" AutoID > 5"); DataRow[] rows1 = dTable.Select(" AutoID > 5", "AuotID ASC");Note that Select method of the DataTable returns the array of rows that matche the filter expression. If you want to loop through all the filtered rows, you can use foreach loop as shown below. In this code, I am adding all the filtered rows into another DataTable.
foreach (DataRow thisRow in rows) {Working with Aggregate functions (Updated on 18-Nov-08)// add values into the datatable dTable1.Rows.Add(thisRow.ItemArray);}
DataRow[] rows22 = dTable.Select("AutoID = max(AutoID)"); string str = "MaxAutoID: " + rows22[0]["AutoID"].ToString();To get the sum of a particular column, we can use Compute method of the DataTable. Compute method of the DataTable takes two argument. The first argument is the expression to compute and second is the filter to limit the rows that evaluate in the expression. If we don't want any filteration (if we need only the sum of the AutoID column for all rows), we can leave the second parameter as blank ("").
object objSum = dTable.Compute("sum(AutoID)", "AutoID > 7"); string sum = "Sum: " + objSum.ToString(); // To get sum of AutoID for all rows of the DataTable object objSum = dTable.Compute("sum(AutoID)", "");
// Sorting DataTableDataView dataView = new DataView(dTable); dataView.Sort = " AutoID DESC, Name DESC"; foreach (DataRowView view in dataView) {Using DataTable.Select() methodResponse.Write(view["Address"].ToString());}
DataRow[] rows = dTable.Select("", "AutoID DESC");
// creating schema definition of the DataTabledTable.WriteXmlSchema(Server.MapPath("~/DataTableSchema.xml")); // Reading XmlSchema from the xml file we just created DataTable dTableXmlSchema = new DataTable(); dTableXmlSchema.ReadXmlSchema(Server.MapPath("~/DataTableSchema.xml"));
// Note: In order to write the DataTable into XML, // you must define the name of the DataTable while creating it // Also if you are planning to read back this XML into DataTable, you should define the XmlWriteMode.WriteSchema too // Otherwise ReadXml method will not understand simple xml file dTable.WriteXml(Server.MapPath("~/DataTable.xml"), XmlWriteMode.WriteSchema); // Loading Data from XML into DataTable DataTable dTableXml = new DataTable(); dTableXml.ReadXml(Server.MapPath("~/DataTable.xml"));If you are planning to read the xml you have just created into the DataTable sometime later then you need to specify XmlWriteMode.WriteSchema too as the 2nd parameter while calling WriteXml method of the DataTable otherwise normally WriteXml method doesn't write schema of the DataTable. In the abscence of the schema, you will get error (DataTable does not support schema inference from Xml) while calling ReadXml method of the DataTable.
Error: “SQL server setup media does not support the language of the OS or does not have ENU localized files. Use the matching language-specific SQL Server media or change the OS locale through Control Panel.”
/// /// Devuelve el nombre del metodo desde el que se invoca este metodo
/// public static string MethodContext()
{
System.Diagnostics.StackFrame stack =
new System.Diagnostics.StackFrame(1);
return stack.GetMethod().Name;
}[ServiceContract(Namespace="http://drojasm.net")] public interface IServicioProductos{ [OperationContract] List<string> ObtenerProductos(int pCantidad); }
public class ServicioProductos : IServicioProductos { public List<string> ObtenerProductos(int pCantidad) { List<string> _productos = new List<string>(); for (int i = 0; i < pCantidad; i++) { _productos.Add("Fruta Número " + i.ToString()); } System.Threading.Thread.Sleep(5000); return _productos; } } }
- digite cuantos elementos quiere en la lista. También vamos a poner dos botones, uno para invocar el servicio sincrónicamente y otro asincrónicamente. Por último, vamos a poner un botón que va a lanzar un MessageBox cuando se le da click; el objetivo de este es demostrar que cuando invocamos el servicio de forma asincrónica, podemos llevar a cabo otras tareas mientras que cuando lo hacemos de forma sincrónica la pantalla se bloquea. El XAML de la pantala es el siguiente:<Window x:Class="ClienteAsincronicoWCF.MainWindow" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Title="MainWindow" Height="350" Width="447"> <Grid> <ListBox Height="197" HorizontalAlignment="Left" Margin="47,74,0,0" Name="lstFrutas" VerticalAlignment="Top" Width="120" /> <Label Content="Frutas" Height="28" HorizontalAlignment="Left" Margin="47,40,0,0" Name="label1" VerticalAlignment="Top" /> <Button Content="Cargar Sincronicamente" Height="23" HorizontalAlignment="Left" Margin="213,220,0,0" Name="btnSincronico" VerticalAlignment="Top" Width="140" Click="btnSincronico_Click" /> <Button Content="Cargar Asincronicamente" Height="23" HorizontalAlignment="Left" Margin="213,249,0,0" Name="btnAsincronico" VerticalAlignment="Top" Width="140" Click="btnAsincronico_Click" /> <Label Content="Cantidad de Productos" Height="28" HorizontalAlignment="Left" Margin="213,146,0,0" Name="label2" VerticalAlignment="Top" /> <TextBox Height="23" HorizontalAlignment="Left" Margin="213,180,0,0" Name="txtCantidad" VerticalAlignment="Top" Width="140" /> <Button Height="75" HorizontalAlignment="Left" Margin="269,40,0,0" Name="button1" VerticalAlignment="Top" Width="75" Click="button1_Click"> <Button.Content> <StackPanel> <Image Height="48" Name="image1" Stretch="Fill" Width="48" Source="/ClienteAsincronicoWCF;component/pens.png" /> <Label Content="Otra Tarea" Height="28" Name="label3" /> StackPanel> Button.Content> Button> Grid> Window>
private void btnSincronico_Click(object sender, RoutedEventArgs e) { lstFrutas.ItemsSource = null; ServicioProductosClient _proxy = new ServicioProductosClient(); lstFrutas.ItemsSource = _proxy.ObtenerProductos(int.Parse(txtCantidad.Text)); }
using ClienteAsincronicoWCF.ReferenciaServicioProductos;
private void btnAsincronico_Click(object sender, RoutedEventArgs e) { lstFrutas.ItemsSource = null; ServicioProductosClient _proxy = new ServicioProductosClient(); AsyncCallback _callBack = delegate(IAsyncResult pResult) { this.Dispatcher.BeginInvoke((Action)delegate { lstFrutas.ItemsSource = _proxy.EndObtenerProductos(pResult); }); }; _proxy.BeginObtenerProductos(int.Parse(txtCantidad.Text), _callBack, _proxy); }
private void button1_Click(object sender, RoutedEventArgs e) { MessageBox.Show("Iniciando otra operación"); }
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