填充:selectcommand.connection属性尚未初始化。我的代码plzzz的错误有什么帮助 [英] Fill: selectcommand.connection property has not been initialized. What error of my code plzzz help
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问题描述
dbconn.Open()
dbadapter.SelectCommand = New OleDb.OleDbCommand
dbadapter.Fill(dbdataset1)
dbconn.Close()
Me.DataGridView1.DataSource = dbdataset1.Tables( 0 )。DefaultView
我尝试了什么:
在vb.net上填写datagridview im newbie
解决方案
您不仅没有初始化Command对象的Connection属性,也没有初始化它的CommandText属性。您如何看待数据库应该知道您想要什么?
如果您只打算使用单个DataTable,那么没有理由使用DataSet - DataAdapter .Fill(..)方法也可以接受一个DataTable作为参数。
你应该使用使用
- OleDb ***的声明 - 对象以安全地释放相关资源。
请查看此CodeProject文章,您将从中学习如何做到这一切:
正确执行数据库操作 [ ^ ]
dbconn.Open()
dbadapter.SelectCommand = New OleDb.OleDbCommand
dbadapter.Fill(dbdataset1)
dbconn.Close()
Me.DataGridView1.DataSource = dbdataset1.Tables(0).DefaultView
What I have tried:
fill datagridview im newbie on vb.net
解决方案
You didn't just not initialize the Connection-property of your Command-object, you also didn't initialize the CommandText-property of it. How do you think the database should know what you want?
Also there's no reason to use a DataSet if you're only going to use a single DataTable - the DataAdapter.Fill(..) method can also accept a DataTable as argument.
And you should be usingusing
-statements for your OleDb***-objects in order to securely free the associated resources.
Please take a look at this CodeProject article, you'll learn from it how to do all this properly:
Properly executing database operations[^]
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