SqlCeDataAdapter.DeleteCommand 属性

获取或设置用于从数据集中删除记录的 SQL 语句。

命名空间：  System.Data.SqlServerCe
程序集：  System.Data.SqlServerCe（在 System.Data.SqlServerCe.dll 中）

语法

声明
Public Property DeleteCommand As SqlCeCommand
    Get
    Set
用法
Dim instance As SqlCeDataAdapter
Dim value As SqlCeCommand

value = instance.DeleteCommand

instance.DeleteCommand = value

public SqlCeCommand DeleteCommand { get; set; }

public:
property SqlCeCommand^ DeleteCommand {
    SqlCeCommand^ get ();
    void set (SqlCeCommand^ value);
}

member DeleteCommand : SqlCeCommand with get, set

function get DeleteCommand () : SqlCeCommand
function set DeleteCommand (value : SqlCeCommand)

属性值

类型：System.Data.SqlServerCe.SqlCeCommand
在 Update 过程中使用的 SqlCeCommand，用以删除数据源中与 DataSet 中已删除的行相对应的记录。

注释

在调用 Update 过程中，如果未设置此属性而且 DataSet 中存在主键信息，那么在设置 SelectCommand 属性并使用 SqlCeCommandBuilder 的情况下，可以自动生成 DeleteCommand。然后，SqlCeCommandBuilder 将生成其他任何未设置的命令。此生成逻辑要求 DataSet 中存在键列信息。

当将 DeleteCommand 分配给以前创建的 SqlCeCommand 时，不克隆 SqlCeCommand。DeleteCommand 维护对以前创建的 SqlCeCommand 对象的引用。

示例

下面的示例创建了一个 SqlCeDataAdapter 并设置了它的一些属性。

Dim cmd As SqlCeCommand = Nothing
Dim adp As SqlCeDataAdapter = Nothing

Try
    adp = New SqlCeDataAdapter()
    Dim conn As New SqlCeConnection("Data Source = MyDatabase.sdf")

    ' Create the SelectCommand
    '
    cmd = conn.CreateCommand()
    cmd.CommandText = "SELECT * FROM Orders WHERE [Ship Country] = @country AND [Ship City] = @city"
    cmd.Parameters.Add("@country", SqlDbType.NVarChar, 15)
    cmd.Parameters.Add("@city", SqlDbType.NVarChar, 15)

    cmd.Parameters("@country").Value = "UK"
    cmd.Parameters("@city").Value = "London"

    adp.SelectCommand = cmd

    ' Create the DeleteCommand
    '
    cmd = conn.CreateCommand()
    cmd.CommandText = "DELETE FROM Orders WHERE [Order ID] = @orderID"

    Dim p As SqlCeParameter = cmd.Parameters.Add("@orderID", SqlDbType.NChar, 5, "Order ID")
    p.SourceVersion = DataRowVersion.Original

    adp.DeleteCommand = cmd

    ' Populate the dataset with the results from the SELECT statement
    '
    Dim ds As New DataSet()
    adp.Fill(ds)

    ' Modify the dataset
    '
    MessageBox.Show("Number of rows: " & ds.Tables(0).Rows.Count)

    ' Delete some rows
    '
    ds.Tables(0).Rows(3).Delete()
    ds.Tables(0).Rows(4).Delete()

    ' This will execute two DELETE statements 
    '
    adp.Update(ds.Tables(0))
Catch e As Exception
    MessageBox.Show(e.Message)
Finally
    If Not Nothing Is adp.SelectCommand Then
        adp.SelectCommand.Dispose()
    End If
    If Not Nothing Is adp.DeleteCommand Then
        adp.DeleteCommand.Dispose()
    End If
End Try

SqlCeCommand cmd = null;
SqlCeDataAdapter adp = null;

try
{
    adp = new SqlCeDataAdapter();
    SqlCeConnection conn = new SqlCeConnection("Data Source = MyDatabase.sdf");

    // Create the SelectCommand
    //
    cmd = conn.CreateCommand();
    cmd.CommandText = "SELECT * FROM Orders WHERE [Ship Country] = @country AND [Ship City] = @city";
    cmd.Parameters.Add("@country", SqlDbType.NVarChar, 15);
    cmd.Parameters.Add("@city", SqlDbType.NVarChar, 15);

    cmd.Parameters["@country"].Value = "UK";
    cmd.Parameters["@city"].Value = "London";

    adp.SelectCommand = cmd;

    // Create the DeleteCommand
    //
    cmd = conn.CreateCommand();
    cmd.CommandText = "DELETE FROM Orders WHERE [Order ID] = @orderID";

    SqlCeParameter p = cmd.Parameters.Add("@orderID", SqlDbType.NChar, 5, "Order ID");
    p.SourceVersion = DataRowVersion.Original;

    adp.DeleteCommand = cmd;

    // Populate the dataset with the results from the SELECT statement
    //
    DataSet ds = new DataSet();
    adp.Fill(ds);

    // Modify the dataset
    //
    MessageBox.Show("Number of rows: " + ds.Tables[0].Rows.Count);

    // Delete some rows
    //
    ds.Tables[0].Rows[3].Delete();
    ds.Tables[0].Rows[4].Delete();

    // This will execute two DELETE statements 
    //
    adp.Update(ds.Tables[0]);
}
catch (Exception e)
{
    MessageBox.Show(e.Message);
}
finally
{
    if (null != adp.SelectCommand) adp.SelectCommand.Dispose();
    if (null != adp.DeleteCommand) adp.DeleteCommand.Dispose();
}

请参阅

参考

SqlCeDataAdapter 类

System.Data.SqlServerCe 命名空间

InsertCommand

SelectCommand

UpdateCommand