Question

在下面的代码中，“当删除行的DataRow集合传递时，更新需要有效的DeleteCommand”。意思？

foreach (DataGridViewRow item in this.dataGridView2.SelectedRows)
{
    fuelStopsDataSet1.Tables[0].Rows[item.Index].Delete();
}

this.fuelStopsTableAdapter.Update(this.fuelStopsDataSet1.FuelStops);

Answer 1

您可以在某些情况下自动创建DeleteCommand（从SelectCommand推断）。

SqlDataAdapter da = new SqlDataAdapter("...SELECT Statement...", connection);
SqlCommandBuilder cmd_b = new SqlCommandBuilder(da); // this already creates 
// the Update- and DeleteCommands for the DA

这是一篇关于它的文章：
http://msdn.microsoft.com/library/vstudio/tf579hcz.aspx

Answer 2

这意味着您使用DataAdapter更新包含已删除DataRows的表格（RowState为Deleted）。然后DataAdapter使用指定的DeleteCommand删除数据库中的此行。但是你没有提供它。

所以你需要提供它。

MSDN示例：

public static SqlDataAdapter CreateCustomerAdapter(
    SqlConnection connection)
{
    SqlDataAdapter adapter = new SqlDataAdapter();

    // Create the SelectCommand.
    SqlCommand command = new SqlCommand("SELECT * FROM Customers " +
        "WHERE Country = @Country AND City = @City", connection);

    // Add the parameters for the SelectCommand.
    command.Parameters.Add("@Country", SqlDbType.NVarChar, 15);
    command.Parameters.Add("@City", SqlDbType.NVarChar, 15);

    adapter.SelectCommand = command;

    // Create the InsertCommand.
    command = new SqlCommand(
        "INSERT INTO Customers (CustomerID, CompanyName) " +
        "VALUES (@CustomerID, @CompanyName)", connection);

    // Add the parameters for the InsertCommand.
    command.Parameters.Add("@CustomerID", SqlDbType.NChar, 5, "CustomerID");
    command.Parameters.Add("@CompanyName", SqlDbType.NVarChar, 40, "CompanyName");

    adapter.InsertCommand = command;

    // Create the UpdateCommand.
    command = new SqlCommand(
        "UPDATE Customers SET CustomerID = @CustomerID, CompanyName = @CompanyName " +
        "WHERE CustomerID = @oldCustomerID", connection);

    // Add the parameters for the UpdateCommand.
    command.Parameters.Add("@CustomerID", SqlDbType.NChar, 5, "CustomerID");
    command.Parameters.Add("@CompanyName", SqlDbType.NVarChar, 40, "CompanyName");
    SqlParameter parameter = command.Parameters.Add(
        "@oldCustomerID", SqlDbType.NChar, 5, "CustomerID");
    parameter.SourceVersion = DataRowVersion.Original;

    adapter.UpdateCommand = command;

    // Create the DeleteCommand.
    command = new SqlCommand(
        "DELETE FROM Customers WHERE CustomerID = @CustomerID", connection);

    // Add the parameters for the DeleteCommand.
    parameter = command.Parameters.Add(
        "@CustomerID", SqlDbType.NChar, 5, "CustomerID");
    parameter.SourceVersion = DataRowVersion.Original;

    adapter.DeleteCommand = command;

    return adapter;
}

最后一个命令是DeleteCommand。

使用DataSet更新TableAdapter - Update需要有效的DeleteCommand错误

2 个答案: