RefreshMode 列舉

定義

命名空間:

System.Data.Linq

組件:

System.Data.Linq.dll

定義 Refresh 方法如何處理開放式並行存取衝突。

public enum class RefreshMode

public enum RefreshMode

type RefreshMode = 

Public Enum RefreshMode

繼承

Object

ValueType

Enum

RefreshMode

欄位

KeepChanges	1	強制讓 Refresh 方法保留已變更的目前值，但以資料庫值來更新其他值。
KeepCurrentValues	0	強制讓 Refresh 方法將原始值與從資料庫中擷取的值交換。 未修改目前的值。
OverwriteCurrentValues	2	強制讓 Refresh 方法使用資料庫中的值來覆寫所有目前值。

範例

下列範例會以資料庫中的值覆寫目前的值。

Northwnd db = new Northwnd("...");
try
{
    db.SubmitChanges(ConflictMode.ContinueOnConflict);
}

catch (ChangeConflictException e)
{
    Console.WriteLine(e.Message);
    foreach (ObjectChangeConflict occ in db.ChangeConflicts)
    {
        // All database values overwrite current values.
        occ.Resolve(RefreshMode.OverwriteCurrentValues);
    }
}

Dim db As New Northwnd("...")

Try
    db.SubmitChanges(ConflictMode.ContinueOnConflict)

Catch ex As ChangeConflictException
    Console.WriteLine(ex.Message)

    For Each occ As ObjectChangeConflict In db.ChangeConflicts
        ' All database values overwrite current values.
        occ.Resolve(Data.Linq.RefreshMode.OverwriteCurrentValues)
    Next

End Try

下列範例示範如何將原始值與從資料庫擷取的值交換。 未修改目前的值。

try
{
    db.SubmitChanges(ConflictMode.ContinueOnConflict);
}

catch (ChangeConflictException e)
{
    Console.WriteLine(e.Message);
    foreach (ObjectChangeConflict occ in db.ChangeConflicts)
    {
        //No database values are merged into current.
        occ.Resolve(RefreshMode.KeepCurrentValues);
    }
}

Try
    db.SubmitChanges(ConflictMode.ContinueOnConflict)

Catch ex As ChangeConflictException
    Console.WriteLine(ex.Message)

    For Each occ As ObjectChangeConflict In db.ChangeConflicts
        ' No database values are merged into current.
        occ.Resolve(Data.Linq.RefreshMode.KeepCurrentValues)
    Next

End Try

下列範例會保留已變更的目前值，但會以資料庫值更新其他值。

try
{
    db.SubmitChanges(ConflictMode.ContinueOnConflict);
}

catch (ChangeConflictException e)
{
    Console.WriteLine(e.Message);
    // Automerge database values for members that client
    // has not modified.
    foreach (ObjectChangeConflict occ in db.ChangeConflicts)
    {
        occ.Resolve(RefreshMode.KeepChanges);
    }
}

// Submit succeeds on second try.
db.SubmitChanges(ConflictMode.FailOnFirstConflict);

Try
    db.SubmitChanges(ConflictMode.ContinueOnConflict)

Catch ex As ChangeConflictException
    Console.WriteLine(ex.Message)

    For Each occ As ObjectChangeConflict In db.ChangeConflicts
        ' Automerge database values into current for members
        ' that client has not modified.
        occ.Resolve(Data.Linq.RefreshMode.KeepChanges)
    Next

End Try

' Submit succeeds on second try.
db.SubmitChanges(ConflictMode.FailOnFirstConflict)

備註

此列舉適用於所有 Refresh 多載。