DataGridViewCell.DefaultNewRowValue 属性

定义

命名空间:

System.Windows.Forms

程序集:

System.Windows.Forms.dll

获取新记录所在行中单元格的默认值。

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

属性值

Object

表示默认值的 Object。

属性

BrowsableAttribute

示例

下面的代码示例演示如何重写DefaultNewRowValue派生自 DataGridViewTextBoxCell的类中的 CalendarCell 属性。 此示例是How to： Host Controls in dataGridView Cells中提供的更大代码示例的一部分，Windows 窗体。

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

注解

DefaultNewRowValue基类DataGridViewCell中的 属性始终返回 null。 但是，可以在派生单元格类中重写此属性以返回其他默认值。

如果单元格位于新记录的行中，则显示此属性返回的值。 当焦点进入新记录的行时， DataGridView.DefaultValuesNeeded 事件的处理程序可以重写此值。

另请参阅

• DataGridView
• Value
• FormattedValue