BindingSource.MoveFirst Methode

public:
 void MoveFirst();

public void MoveFirst ();

member this.MoveFirst : unit -> unit

Public Sub MoveFirst ()

Beispiele

Im folgenden Codebeispiel werden die MoveNextMember , MoveFirst, Currentund Position veranschaulicht. Fügen Sie zum Ausführen dieses Beispiels den Code in ein Formular ein, das den System.Drawing.Drawing2D Namespace importiert und eine BindingSource benannte BindingSource1 und eine Schaltfläche mit dem Namen button1enthält. Ordnen Sie die Form1_Load Methoden und Form1_Paint den Load Ereignissen und Paint für das Formular zu, und ordnen Sie die button1_click -Methode dem Click -Ereignis für button1zu. Visual Basic-Benutzer müssen einen Verweis auf System.Data.dll hinzufügen.

    void Form1_Load(Object^ sender, EventArgs^ e)
    {
        // Set the data source to the Brush type and populate
        // bindingSource1; with some brushes.
        bindingSource1->DataSource = System::Drawing::Brush::typeid;
        bindingSource1->Add(
            gcnew TextureBrush(gcnew Bitmap(Button::typeid, "Button.bmp")));
        bindingSource1->Add(gcnew HatchBrush(HatchStyle::Cross, Color::Red));
        bindingSource1->Add(gcnew SolidBrush(Color::Blue));
    }


private:
    void moveNextButton_Click(Object^ sender, EventArgs^ e)
    {
        // If you are not at the end of the list, move to the next item
        // in the BindingSource.
        if (bindingSource1->Position + 1 < bindingSource1->Count)
        {
            bindingSource1->MoveNext();
        }
        // Otherwise, move back to the first item.
        else
        {
            bindingSource1->MoveFirst();
        }
        // Force the form to repaint.
        this->Invalidate();
    }

    void Form1_Paint(Object^ sender, PaintEventArgs^ e)
    {
        // Get the current item in the BindingSource.
        Brush^ item = (Brush^) bindingSource1->Current;

        // If the current type is a TextureBrush, fill an ellipse.
        if (item->GetType() == TextureBrush::typeid)
        {
            e->Graphics->FillEllipse(item,e->ClipRectangle);
        }
        // If the current type is a HatchBrush, fill a triangle.
        else if (item->GetType() == HatchBrush::typeid)
        {

            e->Graphics->FillPolygon(item, 
                gcnew array<Point> {*gcnew Point(0, 0),
                *gcnew Point(0, 200),
                *gcnew Point(200, 0)});
        }
        // Otherwise, fill a rectangle.
        else
        {
            e->Graphics->FillRectangle(
                (Brush^)bindingSource1->Current, e->ClipRectangle);
        }
    }

void Form1_Load(object sender, EventArgs e)
{
    // Set the data source to the Brush type and populate
    // BindingSource1 with some brushes.
    BindingSource1.DataSource = typeof(System.Drawing.Brush);
    BindingSource1.Add(
        new TextureBrush(new Bitmap(typeof(Button), "Button.bmp")));
    BindingSource1.Add(new HatchBrush(HatchStyle.Cross, Color.Red));
    BindingSource1.Add(new SolidBrush(Color.Blue));
}

private void button1_Click(object sender, EventArgs e)
{
    // If you are not at the end of the list, move to the next item
    // in the BindingSource.
    if (BindingSource1.Position + 1 < BindingSource1.Count)
        BindingSource1.MoveNext();

    // Otherwise, move back to the first item.
    else
        BindingSource1.MoveFirst();

    // Force the form to repaint.
    this.Invalidate();
}

void Form1_Paint(object sender, PaintEventArgs e)
{
    // Get the current item in the BindingSource.
    Brush item = (Brush)BindingSource1.Current;

    // If the current type is a TextureBrush, fill an ellipse.
    if (item.GetType() == typeof(TextureBrush))
        e.Graphics.FillEllipse(item,
           e.ClipRectangle);

    // If the current type is a HatchBrush, fill a triangle.
    else if (item.GetType() == typeof(HatchBrush))
        e.Graphics.FillPolygon(item,
            new Point[] { new Point(0, 0), new Point(0, 200),
            new Point(200, 0)});

    // Otherwise, fill a rectangle.
    else
        e.Graphics.FillRectangle(
            (Brush)BindingSource1.Current, e.ClipRectangle);
}

Sub Form1_Load(ByVal sender As Object, ByVal e As EventArgs) _
    Handles Me.Load

    ' Set the data source to the Brush type and populate
    ' BindingSource1 with some brushes.
    BindingSource1.DataSource = GetType(System.Drawing.Brush)
    BindingSource1.Add(New TextureBrush(New Bitmap(GetType(Button), _
        "Button.bmp")))
    BindingSource1.Add(New HatchBrush(HatchStyle.Cross, Color.Red))
    BindingSource1.Add(New SolidBrush(Color.Blue))

End Sub



Private Sub button1_Click(ByVal sender As Object, ByVal e As EventArgs) _
     Handles button1.Click

    ' If you are not at the end of the list, move to the next item
    ' in the BindingSource.
    If BindingSource1.Position + 1 < BindingSource1.Count Then
        BindingSource1.MoveNext()

        ' Otherwise, move back to the first item.
    Else
        BindingSource1.MoveFirst()
    End If

    ' Force the form to repaint.
    Me.Invalidate()

End Sub


Sub Form1_Paint(ByVal sender As Object, ByVal e As PaintEventArgs)

    ' Get the current item in the BindingSource.
    Dim item As Brush = CType(BindingSource1.Current, Brush)

    ' If the current type is a TextureBrush, fill an ellipse.
    If item.GetType().Equals(GetType(TextureBrush)) Then
        e.Graphics.FillEllipse(item, _
        e.ClipRectangle)

        ' If the current type is a HatchBrush, fill a triangle.
    ElseIf item.GetType().Equals(GetType(HatchBrush)) Then
        e.Graphics.FillPolygon(item, New Point() _
         {New Point(0, 0), New Point(0, 200), New Point(200, 0)})

        ' Otherwise, fill a rectangle.
    Else
        e.Graphics.FillRectangle(item, e.ClipRectangle)
    End If

End Sub

Hinweise

Ändert den aktuellen Wert der Position Eigenschaft in 0, das erste Element in der zugrunde liegenden Datenquelle.

Gilt für:

Weitere Informationen

• List
• Position
• Count
• Current
• MoveNext()
• MovePrevious()
• MoveLast()