大家好，又见面了，我是你们的朋友全栈君。
OleDbConnection对象要先Open(),
然后再Close()
而使用OleDbDataAdapter时,
OleDbConnection不用Open(),也不用关闭
因为OleDbDataAdapter是自动打开和自动关闭的。
而OleDbCommand是需要手动打开的！
OleDbConnection con=new OleDbConnection(“Provider=Microsoft.Jet.OLEDB.4.0; data source=data.mdb”);
con.Open();
OleDbCommand dc=new OleDbCommand(“select name from us where id=2”, con);
textBox1.Text=dc.ExecuteScalar().ToString();
OleDbConnection con=new OleDbConnection(“Provider=Microsoft.Jet.OLEDB.4.0; data source=data.mdb”);
con.Open();
OleDbCommand dc=new OleDbCommand(“insert into us (name) values (11)”, con);
dc.ExecuteNonQuery();
con.Close();
string us=textBox2.Text;
string pa=textBox1.Text;
OleDbConnection con=new OleDbConnection(“Provider=Microsoft.Jet.OLEDB.4.0; data source=data.mdb”);
OleDbCommand oldC=new OleDbCommand(“insert into users (username, userpassword) values (@username, @userpassword)”, con);
oldC.Parameters.Add(“@username”, us);
oldC.Parameters.Add(“@userpassword”, pa);
con.Open();
oldC.ExecuteNonQuery();
con.Close();
MessageBox.Show(“Register successful!”);
this.Dispose();
也有先有OleDbCommand封装select语句，再用OleDbCommand构建OleDbAdapter的
转载于:https://www.cnblogs.com/marvelousone/p/7443819.html
发布者：全栈程序员-站长，转载请注明出处：https://javaforall.net/144548.html原文链接：https://javaforall.net
