'Declaration Public Class Application _ Inherits DispatcherObject _ Implements IQueryAmbient
<Application ............/>
..............................................................................................................................................
Imports Microsoft.VisualBasic Imports System ' STAThread Imports System.Windows ' Application Namespace SDKSample Public Class AppCode Inherits Application ' Entry point method <STAThread> Public Shared Sub Main() Dim app As New AppCode() app.Run() End Sub End Class End Namespace
..............................................................................................................................................
Imports Microsoft.VisualBasic Imports System.Windows ' Application Namespace SDKSample Partial Public Class App Inherits Application End Class End Namespace
<Application .../>
<Application xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" x:Class="SDKSample.App" />
C#
using System.Windows; // Application namespace SDKSample { public partial class App : Application { }..............................................................................................................................................
<Application .../>
public class Application : DispatcherObject, IQueryAmbient
using System; // STAThread using System.Windows; // Application namespace SDKSample { public class AppCode : Application { // Entry point method [STAThread] public static void Main() { AppCode app = new AppCode(); app.Run(); } } }
'Declaration Public Sub New
The following code example demonstrates how to create a ListBox controlthat displays multiple items in columns and can have more than one itemselected in the control's list. The code for the example adds 50 itemsto the ListBox using the Add method of the ListBox::ObjectCollectionclass and then selects three items from the list using the SetSelectedmethod. The code then displays values from theListBox::SelectedObjectCollection collection, through the SelectedItemsproperty, and the ListBox::SelectedIndexCollection, through theSelectedIndices property. This example requires that the code is locatedin and called from a Form
Private Sub button1_Click(sender As Object, e As System.EventArgs) ' Create an instance of the ListBox. Dim listBox1 As New ListBox() ' Set the size and location of the ListBox. listBox1.Size = New System.Drawing.Size(200, 100) listBox1.Location = New System.Drawing.Point(10, 10) ' Add the ListBox to the form. Me.Controls.Add(listBox1) ' Set the ListBox to display items in multiple columns. listBox1.MultiColumn = True ' Set the selection mode to multiple and extended. listBox1.SelectionMode = SelectionMode.MultiExtended ' Shutdown the painting of the ListBox as items are added. listBox1.BeginUpdate() ' Loop through and add 50 items to the ListBox. Dim x As Integer For x = 1 To 50 listBox1.Items.Add("Item " & x.ToString()) Next x ' Allow the ListBox to repaint and display the new items. listBox1.EndUpdate() ' Select three items from the ListBox. listBox1.SetSelected(1, True) listBox1.SetSelected(3, True) listBox1.SetSelected(5, True) ' Display the second selected item in the ListBox to the console. System.Diagnostics.Debug.WriteLine(listBox1.SelectedItems(1).ToString()) ' Display the index of the first selected item in the ListBox. System.Diagnostics.Debug.WriteLine(listBox1.SelectedIndices(0).ToString()) End Sub
public:
ListBox()
The following code example demonstrates how to create a ListBox control
that displays multiple items in columns and can have more than one item
selected in the control's list. The code for the example adds 50 items
to the ListBox using the Add method of the ListBox::ObjectCollection
class and then selects three items from the list using the SetSelected
method. The code then displays values from the
ListBox::SelectedObjectCollection collection, through the SelectedItems
property, and the ListBox::SelectedIndexCollection, through the
SelectedIndices property. This example requires that the code is located
in and called from a Form
void button1_Click( Object^ /*sender*/, System::EventArgs^ /*e*/ ) { // Create an instance of the ListBox. ListBox^ listBox1 = gcnew ListBox; // Set the size and location of the ListBox. listBox1->Size = System::Drawing::Size( 200, 100 ); listBox1->Location = System::Drawing::Point( 10, 10 ); // Add the ListBox to the form. this->Controls->Add( listBox1 ); // Set the ListBox to display items in multiple columns. listBox1->MultiColumn = true; // Set the selection mode to multiple and extended. listBox1->SelectionMode = SelectionMode::MultiExtended; // Shutdown the painting of the ListBox as items are added. listBox1->BeginUpdate(); // Loop through and add 50 items to the ListBox. for ( int x = 1; x <= 50; x++ ) { listBox1->Items->Add( String::Format( "Item {0}", x ) ); } listBox1->EndUpdate(); // Select three items from the ListBox. listBox1->SetSelected( 1, true ); listBox1->SetSelected( 3, true ); listBox1->SetSelected( 5, true ); #if defined(DEBUG) // Display the second selected item in the ListBox to the console. System::Diagnostics::Debug::WriteLine( listBox1->SelectedItems[ 1 ] ); // Display the index of the first selected item in the ListBox. System::Diagnostics::Debug::WriteLine( listBox1->SelectedIndices[ 0 ] ); #endif }
''' <summary>
''' crash test and how to improve your coding
''' </summary>
''' <remarks></remarks>
Public Class Form1
Private Sub Form1_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load
End Sub
''' <summary>
''' pressing button1 will crash he program
''' this crash is the typical crashing type for all beginners
''' </summary>
''' <param name="sender"></param>
''' <param name="e"></param>
''' <remarks></remarks>
Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click
Dim aString() As String 'declare and array only
Try
'a crash will occur and the code won't be able to handle it
MsgBox(aString(0)) ' you do something with the array and and array is nothing
Catch ex As Exception
MsgBox(ex.StackTrace, MsgBoxStyle.Exclamation, ex.Message) 'add basic error message here
End Try
End Sub
End Class
|
''' <summary>
''' crash test and how to improve your coding
''' </summary>
''' <remarks></remarks>
Public Class Form1
Private Sub Form1_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load
End Sub
''' <summary>
''' pressing button1 will crash he program
''' this crash is the typical crashing type for all beginners
''' </summary>
''' <param name="sender"></param>
''' <param name="e"></param>
''' <remarks></remarks>
Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click
Dim aString() As String 'declare and array only
Try
'a crash will occur and the code won't be able to handle it
MsgBox(aString(0)) ' you do something with the array and and array is nothing
Catch ex As Exception
MsgBox(ex.StackTrace) 'add basic error message here
End Try
End Sub
End Class
|
''' <summary>
''' crash test and how to improve your coding
''' </summary>
''' <remarks></remarks>
Public Class Form1
Private Sub Form1_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load
End Sub
''' <summary>
''' pressing button1 will crash he program
''' this crash is the typical crashing type for all beginners
''' </summary>
''' <param name="sender"></param>
''' <param name="e"></param>
''' <remarks></remarks>
Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click
Dim aString() As String 'declare and array only
Try
'a crash will occur and the code won't be able to handle it
MsgBox(aString(0)) ' you do something with the array and and array is nothing
Catch ex As Exception
End Try
End Sub
End Class
|
Try
'a crash will occur and the code won't be able to handle it
MsgBox(aString(0)) ' you do something with the array and and array is nothing
Catch ex As Exception
MsgBox(ex.Message) 'add basic error message here
End Try
|
