Startseite Archive nach Kategorien ".Net" (Seite 31)

Kategorie: .Net

Wichtige Zeichen für Stringoperationen 

' Dezimaltrennzeichen
Public DecimalSeparator As String = System.Globalization.CultureInfo.CurrentCulture.NumberFormat.NumberDecimalSeparator
' Gruppentrennzeichen
Public GroupSeparator As String = System.Globalization.CultureInfo.CurrentCulture.NumberFormat.NumberGroupSeparator
' Negativzeichen
Public NegativeSign As String = System.Globalization.CultureInfo.CurrentCulture.NumberFormat.NegativeSign

String zu Typ wandeln (Parse, TryParse) 

Dim i As Integer = Integer.Parse("100") 
Dim l As Long = Long.Parse("100") 
Dim f As Single = Single.Parse("100.1") 
Dim d As Double = Double.Parse("100.1") 
Dim b As Boolean = Boolean.Parse("True")

Dim dValue As Double

If (Double.TryParse("0,45", dValue) Then
    ...
End If

Zeitspanne messen 

Dim start_time As DateTime
Dim stop_time As DateTime
Dim elapsed_time As TimeSpan

start_time = Now

Funktionsaufruf()

stop_time = Now
elapsed_time = stop_time.Subtract(start_time)
Console.WriteLine(elapsed_time.TotalSeconds().ToString)

dynamisches Array 

Private Function GetMyArray() As SomeClass()
     Dim MyArray As New ArrayList
     Dim CurrentItem As SomeClass ' hat Eigenschaften ID, Name

     For i As Integer = 0 To MyData.Count - 1
          CurrentItem = New SomeClass
          With CurrentItem
               .ID = i
               .Name = "blah " & i.ToString
          End With

          MyArray.Add(CurrentItem)
     Next

     Return DirectCast(MyArray.ToArray(GetType(SomeClass)), SomeClass())
End Function

Text vertikal in einer Grafik ausgeben 

Dim fntScaleFont As New System.Drawing.Font("Arial", 10, FontStyle.Regular)

Dim layout_rect As New RectangleF(0, 0, 18, 64)

Dim string_format As New StringFormat

string_format.Alignment = StringAlignment.Far
string_format.LineAlignment = StringAlignment.Center
string_format.FormatFlags = StringFormatFlags.DirectionVertical
        
m_Graphics.DrawString("Teststring", fntScaleFont, Brushes.Black, layout_rect, string_format)

Grafik drehen 

' gr ... Grafik, die gedreht werden soll
' cx, cy ... Koordinaten
' angle ... Drehwinkel
Private Sub RotateAt(ByVal gr As Graphics, ByVal cx As Integer, ByVal cy As Integer, ByVal angle As Single)
    gr.ResetTransform()
    gr.TranslateTransform(-cx, -cy, Drawing2D.MatrixOrder.Append)
    gr.RotateTransform(angle, Drawing2D.MatrixOrder.Append)
    gr.TranslateTransform(cx, cy, Drawing2D.MatrixOrder.Append)
End Sub

[OleDB] Combobox mit Key/Value Paaren aus einer Datenbank füllen 

Dim DB_OleDBCommand As New System.Data.OleDb.OleDbCommand
Dim DB_OleDBDataAdapter As New System.Data.OleDb.OleDbDataAdapter
Dim dsFuel As New DataSet

DB_OleDBCommand.Connection = frmMain.DB_OleDBConnection

dsFuel.Clear()
DB_OleDBCommand.CommandText = "SELECT ID, Name FROM Users ORDER BY Name"

DB_OleDBDataAdapter.SelectCommand = DB_OleDBCommand
DB_OleDBDataAdapter.Fill(dsFuel)

With cbFuel
    .Items.Clear()
    .DataSource = dsFuel.Tables(0)
    .DisplayMember = "Name"
    .ValueMember = "ID"
End With

' Key/Value Paare auslesen/setzen

Dim Key As String = cbFuel.SelectedValue.ToString() ' auslesen
cbFuel.SelectedValue = 10 ' setzen