LayoutEngine.Layout(Object, LayoutEventArgs) 方法

定義

命名空間:

System.Windows.Forms.Layout

組件:

System.Windows.Forms.dll

要求配置引擎執行一個配置作業。

public:
 virtual bool Layout(System::Object ^ container, System::Windows::Forms::LayoutEventArgs ^ layoutEventArgs);

public virtual bool Layout (object container, System.Windows.Forms.LayoutEventArgs layoutEventArgs);

abstract member Layout : obj * System.Windows.Forms.LayoutEventArgs -> bool
override this.Layout : obj * System.Windows.Forms.LayoutEventArgs -> bool

Public Overridable Function Layout (container As Object, layoutEventArgs As LayoutEventArgs) As Boolean

參數

container

Object

配置引擎將在其中作業的容器。

layoutEventArgs

LayoutEventArgs

Layout 事件的事件引數。

傳回

Boolean

如果 container 的父代 (Parent) 應該再次執行配置，則為 true，否則為 false。

例外狀況

NotSupportedException

container 不是 LayoutEngine 可以在上面執行配置的型別。

範例

下列程式碼範例示範如何使用 Layout 方法來實作自訂版面配置行為。 此程式碼範例是針對 類別提供的較大範例的 LayoutEngine 一部分。

public:
    virtual bool Layout(Object^ container,
        LayoutEventArgs^ layoutEventArgs) override
    {
        Control^ parent = nullptr;
        try
        {
            parent = (Control ^) container;
        }
        catch (InvalidCastException^ ex)
        {
            throw gcnew ArgumentException(
                "The parameter 'container' must be a control", "container", ex);
        }
        // Use DisplayRectangle so that parent.Padding is honored.
        Rectangle parentDisplayRectangle = parent->DisplayRectangle;
        Point nextControlLocation = parentDisplayRectangle.Location;

        for each (Control^ currentControl in parent->Controls)
        {
            // Only apply layout to visible controls.
            if (!currentControl->Visible)
            {
                continue;
            }

            // Respect the margin of the control:
            // shift over the left and the top.
            nextControlLocation.Offset(currentControl->Margin.Left,
                currentControl->Margin.Top);

            // Set the location of the control.
            currentControl->Location = nextControlLocation;

            // Set the autosized controls to their
            // autosized heights.
            if (currentControl->AutoSize)
            {
                currentControl->Size = currentControl->GetPreferredSize(
                    parentDisplayRectangle.Size);
            }

            // Move X back to the display rectangle origin.
            nextControlLocation.X = parentDisplayRectangle.X;

            // Increment Y by the height of the control
            // and the bottom margin.
            nextControlLocation.Y += currentControl->Height +
                currentControl->Margin.Bottom;
        }

        // Optional: Return whether or not the container's
        // parent should perform layout as a result of this
        // layout. Some layout engines return the value of
        // the container's AutoSize property.

        return false;
    }

public override bool Layout(
    object container,
    LayoutEventArgs layoutEventArgs)
{
    Control parent = container as Control;

    // Use DisplayRectangle so that parent.Padding is honored.
    Rectangle parentDisplayRectangle = parent.DisplayRectangle;
    Point nextControlLocation = parentDisplayRectangle.Location;

    foreach (Control c in parent.Controls)
    {
        // Only apply layout to visible controls.
        if (!c.Visible)
        {
            continue;
        }

        // Respect the margin of the control:
        // shift over the left and the top.
        nextControlLocation.Offset(c.Margin.Left, c.Margin.Top);

        // Set the location of the control.
        c.Location = nextControlLocation;

        // Set the autosized controls to their 
        // autosized heights.
        if (c.AutoSize)
        {
            c.Size = c.GetPreferredSize(parentDisplayRectangle.Size);
        }

        // Move X back to the display rectangle origin.
        nextControlLocation.X = parentDisplayRectangle.X;

        // Increment Y by the height of the control 
        // and the bottom margin.
        nextControlLocation.Y += c.Height + c.Margin.Bottom;
    }

    // Optional: Return whether or not the container's 
    // parent should perform layout as a result of this 
    // layout. Some layout engines return the value of 
    // the container's AutoSize property.

    return false;
}

Public Overrides Function Layout( _
ByVal container As Object, _
ByVal layoutEventArgs As LayoutEventArgs) As Boolean

    Dim parent As Control = container

    ' Use DisplayRectangle so that parent.Padding is honored.
    Dim parentDisplayRectangle As Rectangle = parent.DisplayRectangle
    Dim nextControlLocation As Point = parentDisplayRectangle.Location

    Dim c As Control
    For Each c In parent.Controls

        ' Only apply layout to visible controls.
        If c.Visible <> True Then
            Continue For
        End If

        ' Respect the margin of the control:
        ' shift over the left and the top.
        nextControlLocation.Offset(c.Margin.Left, c.Margin.Top)

        ' Set the location of the control.
        c.Location = nextControlLocation

        ' Set the autosized controls to their 
        ' autosized heights.
        If c.AutoSize Then
            c.Size = c.GetPreferredSize(parentDisplayRectangle.Size)
        End If

        ' Move X back to the display rectangle origin.
        nextControlLocation.X = parentDisplayRectangle.X

        ' Increment Y by the height of the control 
        ' and the bottom margin.
        nextControlLocation.Y += c.Height + c.Margin.Bottom
    Next c

    ' Optional: Return whether or not the container's 
    ' parent should perform layout as a result of this 
    ' layout. Some layout engines return the value of 
    ' the container's AutoSize property.
    Return False

End Function

備註

當配置引擎在 參數上 container 執行配置作業時，就會呼叫這個方法。 您可以檢查 、 AffectedComponent 和 AffectedControl 屬性 layoutEventArgs 的值 AffectedProperty ，以決定是否需要配置作業。

給繼承者的注意事項

Layout(Object, LayoutEventArgs)覆寫 方法以提供自訂版面配置行為。

配置 參數的內容 container 時，請務必檢查 Visible 每個子控制項的 屬性。

如果您的版面配置引擎邏輯決定容器的父代應該再次執行配置，則傳回 true 。 例如，當版面配置引擎調整子控制項的大小，並判斷容器的大小必須增加以容納新版面配置時，可能會發生這種情況。

另請參閱

• LayoutEventArgs
• 作法：實作自訂配置引擎