Random thoughts about .Net development
CS2 is capable of indexing source code files (at the moment only C# code can be parsed) and searching among them with various parameters, like class, property and method names, as well as full-text queries.
The main user interface for interacting with the search engine is an ASP.NET website built for version 2.0 of the .NET framework .
Download CS2 Search Engine
[Via dotnetkicks.com]
DataGridView supports the special mode (Virtual Mode). The basic idea is that inside the control not stored any data.
In given below example of the primitive electronic table, the data stored in the hashtable.The electronic table has a large amount of cells. In this example the number of cells equals to 100000 lines * 100 columns = 10000000. Also the programm save and loads changed cells on the disk
Note: The SerializableDictionary can be found here
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.IO;
using System.Text;
using System.Windows.Forms;
using System.Xml.Serialization;
namespace Devintelligence.Example {
public partial class Form1 : Form
{
#region Fields
public SerializableDictionary<string, int> data = new SerializableDictionary<string, int>();
private Font systemFont;
private XmlSerializer serializer = new XmlSerializer(typeof(SerializableDictionary<string, int>));
#endregion
public Form1()
{
InitializeComponent();
}
private void Form1_Load(object sender, EventArgs e)
{
if (File.Exists(FilePath))
{
// load from file & desirialize
using (FileStream filestream = File.OpenRead(FilePath))
{
data = serializer.Deserialize(filestream) as SerializableDictionary<string, int>;
}
}
((ISupportInitialize)dataGridView1).BeginInit();
dataGridView1.VirtualMode = true;
dataGridView1.CellValueNeeded += new DataGridViewCellValueEventHandler(dataGridView1_CellValueNeeded);
dataGridView1.CellValuePushed += new DataGridViewCellValueEventHandler(dataGridView1_CellValuePushed);
// create columns
for (int i = 0; i < 100 ; i++)
{
string name = string.Format("{0}", i);
dataGridView1.Columns.Add(name, name);
}
dataGridView1.RowCount = 100000;
systemFont = new Font(dataGridView1.Font,FontStyle.Bold);
((ISupportInitialize)dataGridView1).EndInit();
}
/// <summary>
/// Calculates the unique hash key based on row and column indexes.
/// </summary>
/// <param name="rowIndex">Index of the row.</param>
/// <param name="columnIndex">Index of the column.</param>
/// <returns></returns>
private static string CalculateKey(int rowIndex, int columnIndex)
{
return string.Format("{0}_{1}", rowIndex, columnIndex);
}
/// <summary>
/// Handles the CellValuePushed event of the dataGridView1 control.
/// </summary>
/// <param name="sender">The source of the event.</param>
/// <param name="e">The <see cref="T:System.Windows.Forms.DataGridViewCellValueEventArgs"/>
/// instance containing the event data.</param>
void dataGridView1_CellValuePushed(object sender, DataGridViewCellValueEventArgs e)
{
data[CalculateKey(e.RowIndex, e.ColumnIndex)] = Convert.ToInt32(e.Value);
// mark changed cells
dataGridView1[e.ColumnIndex, e.RowIndex].Style.BackColor = Color.LightPink;
dataGridView1[e.ColumnIndex, e.RowIndex].Style.Font = systemFont;
}
/// <summary>
/// Handles the CellValueNeeded event of the dataGridView1 control.
/// </summary>
/// <param name="sender">The source of the event.</param>
/// <param name="e">The <see cref="T:System.Windows.Forms.DataGridViewCellValueEventArgs"/>
/// instance containing the event data.</param>
void dataGridView1_CellValueNeeded(object sender, DataGridViewCellValueEventArgs e)
{
int value;
if (data.TryGetValue(CalculateKey(e.RowIndex, e.ColumnIndex), out value))
{
e.Value = value;
// mark changed cells
dataGridView1[e.ColumnIndex, e.RowIndex].Style.BackColor = Color.LightPink;
dataGridView1[e.ColumnIndex, e.RowIndex].Style.Font = systemFont;
}
else
{
e.Value = e.ColumnIndex*e.RowIndex;
}
}
private static string FilePath
{
get
{
// the data file will be saved in file named data.xml
return Path.Combine(Application.StartupPath, "data.xml");
}
}
private void Form1_FormClosing(object sender, FormClosingEventArgs e)
{
// serialize & save entered data
using (FileStream filestream = File.Open(FilePath, FileMode.Create))
{
serializer.Serialize(filestream, data);
}
}
}
}
The easiest way to validate a certain property is using the PropertyValueChanged event.The code bellow shows how to limit the valid range of Age property to be 1-150
using System.Windows.Forms;
namespace WindowsApplication1
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
//init person object
Person person = new Person();
person.FirstName = "George";
person.Age = 33;
propertyGrid.SelectedObject = person;
propertyGrid.PropertyValueChanged+= new PropertyValueChangedEventHandler( propertyGrid_PropertyValueChanged );
}
private void propertyGrid_PropertyValueChanged(object s, PropertyValueChangedEventArgs e)
{
if (e.ChangedItem.Label == "Age" && !IsAgeValid((int)e.ChangedItem.Value) )
{
// the entered age value is wrong - show error message
e.ChangedItem.PropertyDescriptor.SetValue( propertyGrid.SelectedObject, e.OldValue);
MessageBox.Show("Wrong age", "Error", MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
}
}
///<summary>
/// Determines whether age is valid
/// </summary>
/// <param name="age">The age.</param>
/// <returns>
/// <c>true</c> if is age valid ; otherwise, <c>false</c>.
/// </returns>
private static bool IsAgeValid( int age )
{
return ((age > 0) && (age < 150));
}
}
}
Technorati tags: propertygrid, dotnet, programming
I will use the following XML document in the example below.
<?xml version="1.0" encoding="utf-8" ?>
<users>
<user FirstName="Tom" LastName="Adams" Age="23" />
<user FirstName="Jhon" LastName="Brams" Age="17" />
<user FirstName="Bill" LastName="Smith" Age="33" />
</users>
The code prints out all the user nodes of the users node that have an age with a value greater than 17.
// Read the xml from resource file
string xml = Resources.Users;
using (StringReader sr = new StringReader(xml))
{
XPathDocument document = new XPathDocument(sr);
XPathNavigator navigator = document.CreateNavigator();
XmlNamespaceManager ns = new XmlNamespaceManager(navigator.NameTable);
//Selects all the user nodes of the users node that
// have an age with a value greater than 17
XPathNodeIterator it = navigator.Select("/users/user[@Age>17]");
while (it.MoveNext())
{
// access the atributes
string firstName = it.Current.GetAttribute("FirstName", ns.DefaultNamespace);
string lastName = it.Current.GetAttribute("LastName", ns.DefaultNamespace);
// Print out
Console.WriteLine( "{0} {1}", firstName, lastName );
}
}
Inspired by PHP String Functions that are missing in .Net.
Below is a list of the method names and descriptions in the string library.
