C# Access 连接 哪里有错？

来源：百度知道 编辑：UC知道 时间：2024/05/12 20:28:39
AccessPath 为ACCESS库的路径，连接的时候报错为:
未将对象引用设置到对象的实例,请问各位大侠哪里有错，不甚感激
以下为代码：
string connectionstring = "PROVIDER=Microsoft.Jet.OLEDB.4.0;DataSource=" + AccessPath+";pwd=custom;";
OleDbConnection conn = new OleDbConnection(connectionstring);
OleDbTransaction transactionManager = null;

try
{
transactionManager = conn.BeginTransaction();
OleDbCommand comm = new OleDbCommand(sql, conn,transactionManager);

conn.Open();
comm.ExecuteNonQuery();

transactionManager.Commit();
comm.Dispose();
transactionManager.Dispose();
}
catch (Exception e)
{
transactionManager.Rollback();
throw e;
}
finally

你的sql语句呢？OleDbCommand comm = new OleDbCommand(sql, conn,transactionManager);
。。。。。。。。。。。。。。。。。。。。。。。。。。。。下面是我的。
string db = Server.MapPath("web.mdb");
string ConnectionStr = "Data Source=" + db +";Mode=Share Deny None;Jet OLEDB:Engine Type=5;Provider=Microsoft.Jet.OLEDB.4.0";

OleDbConnection conn = new OleDbConnection(ConnectionStr);
conn.Open();
string str = "insert into users(username,password1) values('" + username.Text + "','" +this.TextBox2.Text+ "')";

try
{
OleDbCommand cmd = new OleDbCommand(str, conn);
cmd.ExecuteNonQuery();

conn.Close();
this.Label1.Text = "注册成功。";
}
catch
{
conn.Close();
this.Label1.Text = "注册失败，用户已经存在！";
}

s