DataGridViewCell.DefaultNewRowValue 屬性

定義

命名空間:

System.Windows.Forms

組件:

System.Windows.Forms.dll

取得新資料錄之資料列中儲存格的預設值。

public:
 virtual property System::Object ^ DefaultNewRowValue { System::Object ^ get(); };

[System.ComponentModel.Browsable(false)]
public virtual object DefaultNewRowValue { get; }

[<System.ComponentModel.Browsable(false)>]
member this.DefaultNewRowValue : obj

Public Overridable ReadOnly Property DefaultNewRowValue As Object

屬性值

Object

Object，表示預設值。

屬性

BrowsableAttribute

範例

下列程式碼範例示範如何覆寫 DefaultNewRowValue 衍生自 DataGridViewTextBoxCell 的類別中的 CalendarCell 屬性。 此範例是How to： Host Controls in Windows Forms DataGridView Cells中提供的較大程式碼範例的一部分。

public class CalendarCell : DataGridViewTextBoxCell
{

    public CalendarCell()
        : base()
    {
        // Use the short date format.
        this.Style.Format = "d";
    }

    public override void InitializeEditingControl(int rowIndex, object 
        initialFormattedValue, DataGridViewCellStyle dataGridViewCellStyle)
    {
        // Set the value of the editing control to the current cell value.
        base.InitializeEditingControl(rowIndex, initialFormattedValue, 
            dataGridViewCellStyle);
        CalendarEditingControl ctl = 
            DataGridView.EditingControl as CalendarEditingControl;
        // Use the default row value when Value property is null.
        if (this.Value == null)
        {
            ctl.Value = (DateTime)this.DefaultNewRowValue;
        }
        else
        {
            ctl.Value = (DateTime)this.Value;
        }
    }

    public override Type EditType
    {
        get
        {
            // Return the type of the editing control that CalendarCell uses.
            return typeof(CalendarEditingControl);
        }
    }

    public override Type ValueType
    {
        get
        {
            // Return the type of the value that CalendarCell contains.
            
            return typeof(DateTime);
        }
    }

    public override object DefaultNewRowValue
    {
        get
        {
            // Use the current date and time as the default value.
            return DateTime.Now;
        }
    }
}

Public Class CalendarCell
    Inherits DataGridViewTextBoxCell

    Public Sub New()
        ' Use the short date format.
        Me.Style.Format = "d"
    End Sub

    Public Overrides Sub InitializeEditingControl(ByVal rowIndex As Integer, _
        ByVal initialFormattedValue As Object, _
        ByVal dataGridViewCellStyle As DataGridViewCellStyle)

        ' Set the value of the editing control to the current cell value.
        MyBase.InitializeEditingControl(rowIndex, initialFormattedValue, _
            dataGridViewCellStyle)

        Dim ctl As CalendarEditingControl = _
            CType(DataGridView.EditingControl, CalendarEditingControl)

        ' Use the default row value when Value property is null.
        If (Me.Value Is Nothing) Then
            ctl.Value = CType(Me.DefaultNewRowValue, DateTime)
        Else
            ctl.Value = CType(Me.Value, DateTime)
        End If
    End Sub

    Public Overrides ReadOnly Property EditType() As Type
        Get
            ' Return the type of the editing control that CalendarCell uses.
            Return GetType(CalendarEditingControl)
        End Get
    End Property

    Public Overrides ReadOnly Property ValueType() As Type
        Get
            ' Return the type of the value that CalendarCell contains.
            Return GetType(DateTime)
        End Get
    End Property

    Public Overrides ReadOnly Property DefaultNewRowValue() As Object
        Get
            ' Use the current date and time as the default value.
            Return DateTime.Now
        End Get
    End Property

End Class

備註

DefaultNewRowValue基類 DataGridViewCell 中的 屬性一律會傳 null 回 。 不過，這個屬性可以在衍生的資料格類別中覆寫，以傳回其他預設值。

如果儲存格位於新記錄的資料列中，則會顯示這個屬性所傳回的值。 當焦點進入新記錄的資料列時，事件處理常式 DataGridView.DefaultValuesNeeded 可以覆寫此值。

另請參閱

• DataGridView
• Value
• FormattedValue