JOINed表上的TableAdapter UpdateCommand [英] TableAdapter UpdateCommand on JOINed table

问题描述

假设我有一个从TableAdapter加载的DataGridView，其内容来自2个JOINed表，因此表C为：

Suppose I have a DataGridView that is loading from a TableAdapter whose content is from 2 JOINed tables, so Table C is:

SELECT A.*, B.name LEFT JOIN B ON B.id = A.b_id

$我知道，b $ b

向导没有为此生成UpdateCommand。但是，如果表中的数据几乎全部来自表A，并且仅将表B联接起来以提供表A中id所引用的数据的名称，那么我是否可以提供自己的UpdateCommand来更新用户（如果用户更改了表A）

No UpdateCommand is generated for this by the wizard, I know. However, if the data of the table is almost entirely from Table A, and Table B is only joined in to provide the name of data referenced by id in Table A, can I just supply my own UpdateCommand that updates Table A if the user changes a value in the DataGridView?

就是说，我想将表C的UpdateCommand设置为：

That is, I would like to set Table C's UpdateCommand to:

UPDATE A SET value = [[new value]] WHERE id = [[current item]]

如果情况变得更糟，我可以为用户提供一个对话框，以输入新值并以这种方式进行操作。似乎像上面那样做要简单得多。

If worse comes to worse, I can make a dialog for the user to enter their new value into and do it that way. It just seems like it would be a lot simpler to do it as above. Will that method work?

推荐答案

您可以在 DataAdapter 。您可以找到在MSDN上很好的演练

You can do exactly what you want within the confines of the DataAdapter. You can find a good walkthrough on MSDN.

没有看到您的代码，适配器的设置可能看起来像这样：

Without seeing your code, the setup of your adapter might look something like this:

var dataAdapter = new SqlDataAdapter(
    "SELECT A.*, B.name FROM A LEFT JOIN B ON B.id = A.b_id", sqlConn);

var dataAdapter.UpdateCommand = new SqlCommand(
    "UPDATE A SET value = @Value WHERE id = @Id", sqlConn);

// Define the parameters to be used in the update command.
dataAdapter.UpdateCommand.Parameters.Add(
    "@Value", SqlDbType.NVarChar, 100, "Value_Column_Name");

dataAdapter.UpdateCommand.Parameters.Add(
    new SqlParameter("@Id", SqlDbType.Int)
    {
        SourceColumn = "Id_Column_Name"
    });

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