private void button1_Click(object sender, EventArgs e)
        {
            if (comboBox1.Text == "")
                MessageBox.Show("用户名不能为空");
            else
            if (textBox1.Text == "")
                MessageBox.Show("请输入密码");
            string name = comboBox1.Text.Trim();
            string password = textBox1.Text.Trim();
            string path = Application.StartupPath.Substring(0, Application.StartupPath.Substring(0, Application.StartupPath.LastIndexOf("\\")).LastIndexOf("\\"));
            path += @"\1.mdb";
            string constr = "Provider=Microsoft.Jet.OLEDB.4.0;Data source=" + path;
            OleDbConnection conn = new OleDbConnection(constr);
                       conn.Open();
                       OleDbCommand cmd = new OleDbCommand();
                        = "select * FROM DB_user where user_id='" + name + "' and password='" + password + "'";
                  
    Int32 count = Convert.ToInt32(cmd.ExecuteScalar()); //提示说未初始化……
            

            if (count>0)
            {
                MessageBox.Show("OK");
            }
            else
            {
                MessageBox.Show("NO");
            }
            
        }


   Int32 count = Convert.ToInt32(cmd.ExecuteScalar()); //提示说未初始化……
   请各位给看看，教教小弟，看看是哪里的问题

private void button1_Click(object sender, EventArgs e)
        {
            if (comboBox1.Text == "")
                MessageBox.Show("用户名不能为空");
            else
            if (textBox1.Text == "")
                MessageBox.Show("请输入密码");
 
            string name = comboBox1.Text.Trim();
            string password = textBox1.Text.Trim();
 
            string path = Application.StartupPath.Substring(0, Application.StartupPath.Substring(0, Application.StartupPath.LastIndexOf("\\")).LastIndexOf("\\"));
            path += @"\1.mdb";
            string constr = "Provider=Microsoft.Jet.OLEDB.4.0;Data source=" + path;
            OleDbConnection conn = new OleDbConnection(constr);
            conn.Open();
            OleDbCommand command = new OleDbCommand("select * FROM DB_user where user_id='" + name + "' and password='" + password + "'", conn);
            OleDbDataReader read = command.ExecuteReader();
            read.Read();
 
            if (read.HasRows)
            {
                MessageBox.Show("OK");
            }
            else
            {
                MessageBox.Show("NO");
            }

        }

 OleDbDataReader read = command.ExecuteReader();
这里也提示类型不匹配，我都搞晕了
如何转换呢？

已经解决，是因为Password，在数据库中我用的是数值型，导致出错……
在此谢过各位帮助过我的朋友

目前只知道SQL

这个是什么 问题  啊，不咋懂