BindingSource.MoveFirst 方法

定義

移至清單中的第一個項目。Moves to the first item in the list.

public:
 void MoveFirst();
public void MoveFirst ();
member this.MoveFirst : unit -> unit
Public Sub MoveFirst ()

範例

下列程式碼範例將示範 MoveNextMoveFirstCurrentPosition 成員。The following code example demonstrates the MoveNext, MoveFirst, Current, and Position members. 若要執行這個範例,請將程式碼貼到匯入命名空間的表單中,並包含名為的和名為的 System.Drawing.Drawing2D BindingSource BindingSource1 按鈕 button1To run this example, paste the code into a form that imports the System.Drawing.Drawing2D namespace and contains a BindingSource named BindingSource1 and a button named button1. Form1_LoadForm1_Paint 方法與 Load 表單的和事件建立關聯 Paint ,並將 button1_click 方法與的事件產生關聯 Click button1Associate the Form1_Load and Form1_Paint methods with the Load and Paint events for the form, and associate the button1_click method with the Click event for button1. Visual Basic 使用者將需要新增 System.Data.dll 的參考。Visual Basic users will need to add a reference to System.Data.dll.

    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

備註

將屬性的目前值變更 Position 為0,即基礎資料來源中的第一個專案。Changes the current value of the Position property to 0, the first item in the underlying data source.

適用於

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