c#统计人数，显示不存在此列数据，但数据库里有此列数据

Question

private void button4_Click(object sender, EventArgs e)
        {
            DBConnect();
            oledbCon.Open();
            string cmdstr = @"select count(*) from 学生基本信息 where 性别 = '女'";
            OleDbCommand cmd = new OleDbCommand(cmdstr, oledbCon);
            OleDbDataReader reader = cmd.ExecuteReader();
            
            if (reader.HasRows)
            {
                
                int count = reader.GetInt32(0);
                richTextBox1.Text = "女生的人数 =" + count;
            }
        }

 

Answer 1

你这个没链接到数据库吧，你可以参考一下这段代码

private void button4_Click(object sender, EventArgs e)
        {
            OleDbConnection conn;
            string M = "Provider=Microsoft.Jet.Oledb.4.0;Data Source=d:\\northwind.mdb";
            conn = new OleDbConnection(M);
            conn.Open();
            string cmdstr = @"select count(*) from 学生基本信息 where 性别 = '女'";
            OleDbCommand cmd = new OleDbCommand(cmdstr, conn);
            OleDbDataReader reader = cmd.ExecuteReader();
            if (reader.HasRows)
            {
                int count = reader.GetInt32(0);
                richTextBox1.Text = "女生的人数 =" + count;
            }
        }