如何将DataTable ID与DB同步?

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问题描述

我正在用C#开发一个简单的DB应用程序.我是一个完全的C#初学者，所以请对我轻松一点:)在我的应用程序中，我有一个DB，其表包含3列(ID +两个数据字段)，还有一个带有显示此内容的ListBox的简单表单表，两个允许输入要存储在DB中的数据的文本框和两个按钮:新建"和删除". ListBox DataSource设置为在简单的SELECT查询上创建的DataTable对象.我正在使用MySQL数据库，这可能是与MySQL连接器有关的问题，但是我可能只是想念一些东西.

I am developing a simple DB application in C#. I am a complete C# beginner, so please be easy on me :) In my application I have a DB with table containing 3 columns (ID + two data fields), and also a simple form with a ListBox displaying contents of this table, two TextBoxes allowing to enter data to be stored in DB, and two Buttons: Create New and Delete. ListBox DataSource is set to a DataTable object created on simple SELECT query. I am using a MySQL database and this could be problem related to MySQL connector, but also I might be simply missing something.

现在，一切对我来说都很好，我能够创建这样的新记录:

Now, everything was fine for me and I was able to create a new record like this:

// this is the DataTable used as ListBox data source
DataTable t = tag_.Table;
DataRow newRow = t.NewRow();

newRow.BeginEdit();
newRow["name"] = txtTagName.Text.Trim();
newRow["description"] = txtDescriptionName.Text.Trim();
newRow.EndEdit();

t.Rows.Add(newRow);

try
{

//这将调用daTag_.Update(dsTag_，TABLE)，其中daTag_是MySqlDataAdapter，dsTag_是DataSet，而TABLE是表名: tag_.Update();}抓(MySqlException ex){ MySQLExceptionHandler.Show(ex); tag_.RejectChanges();}

// this calls daTag_.Update(dsTag_, TABLE), where daTag_ is MySqlDataAdapter, dsTag_ is the DataSet and TABLE is the table name:) tag_.Update();}catch (MySqlException ex){ MySQLExceptionHandler.Show(ex); tag_.RejectChanges();}

在我发现我需要使用记录的ID之前(这无关紧要)，这一直很好.因此，我还必须从数据库中选择ID.这就是我的问题开始的地方.创建新的DataRow时，我将NULL放入ID字段，以便获取来自AUTO_INCREMENT的新值.成功调用Update()之后，数据将以自动生成的ID值存储在数据库中，但是添加了行的DataTable对象仍然保留已成功插入到数据库中的行ID的NULL值. 所以:

This was working fine until I found that I need to use the records' ID (doesn't matter for what). So I had to select also the ID from DB. And this is where my problems started. When creating a new DataRow, I am putting NULL into ID field, so that it gets new value from AUTO_INCREMENT. After successful call to Update(), the data gets stored in the DB with auto-generated ID value, BUT the DataTable object, to which the row was added, still holds the NULL value for the ID of Row successfuly inserted into DB. So:

在我的应用程序中，我有一个DataTable，其中DataRow的ID字段的ID字段中包含NULL
在我的数据库中，我有一条具有自动生成的ID值的新记录.

因此，DataTable和DB之间的数据不同步.现在您可以想象如果我尝试删除刚插入的行将会发生什么. NULL将以某种方式转换为0并...

So the data is not synchronized between the DataTable and DB. Now you can imagine what will happen if I try to DELETE the row I just inserted. The NULL will get somehow translated to 0 and...

我为此提出了以下解决方案:

I came up with following solution for this:

try {

    // this calls daTag_.Update(dsTag_, TABLE), where daTag_ is MySqlDataAdapter, dsTag_ is the DataSet and TABLE is the table name:)
    tag_.Update();
    newRow["id"] = tag_.LastInsertedId;
    newRow.AcceptChanges();
}
catch (MySqlException ex)
{
    MySQLExceptionHandler.Show(ex);
    tag_.RejectChanges();
}

这项工作正常，但我必须记住每次插入时的这一额外更改，在我看来，这很像黑客.有没有更好的解决方案来使DataTable在插入时同步?

This works OK, but I have to remember about this additional change on every insert, and it seems to me quite like a hack. Is there any better solution to get DataTable synchronized on insert?

your

如何将DataTable ID与DB同步?

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