Question

我写了一个关于客户注册的程序。客户inf。保存了txt文件。和他们的depts保存访问数据库。我想从小到大排序。我实际上可以对depts进行排序，但是，我想用一些cutome来排序depts。我该怎么办？

private void button2_Click(object sender, EventArgs e)
    {
        //listBox3.Items.Clear();
        OleDbCommand komut = new OleDbCommand();

        conn.Open();


        OleDbCommand cmd = new OleDbCommand(" SELECT RemainingDept FROM Dept_Tbl  ", conn);


        OleDbDataReader dr = cmd.ExecuteReader();

        List<string> liste = new List<string>();


        while ((dr.Read()))
        {

            liste.Add(dr["RemainingDept"].ToString());

        }

        string[] A = liste.ToArray();

        int[] B;
        B = Array.ConvertAll<string, int>(A, int.Parse);

        int tmp;
        for (int i = 0; i <B.Length ; i++)
        {
            for (int j=B.Length-1; j>i; j--)
            {
                if (B[j - 1] > B[j])
                {
                    tmp = B[j - 1];
                    B[j - 1] = B[j];
                    B[j] = tmp;

                }
            }

        }


        listBox3.Items.Clear(); 
        for (int i = 0; i < B.Length; i++)
        {
            listBox3.Items.Add( B[i].ToString());
        }

        conn.Close();
    }
} 

    }

示例：

我的列表框就像这段代码：

30

40

70

我想看到列表框，如：

2 30

1 40

3 70

Answer 1

将您的查询更改为SELECT ID, RemainingDept FROM Dept_Tbl ORDER BY RemainingDept DESC。
摆脱排序代码
将读取行更改为：liste.Add(dr["ID"] + " " + dr["RemainingDept"]);

Answer 2

1。班级方法：

public class Department
{
    public int ID { get; set; }
    public int RemainingDept { get; set; }
}

private void button2_Click(object sender, EventArgs e)
{

    List<Department> liste = new List<Department>();

    OleDbCommand cmd = new OleDbCommand("SELECT ID, RemainingDept FROM Dept_Tbl ORDER BY RemainingDept", conn);
    OleDbDataReader dr = cmd.ExecuteReader();

    while (dr.Read())
    {
        var dept = new Department()
        {
            ID = Convert.ToInt32(dr["ID"]),
            RemainingDept = Convert.ToInt32(dr["RemainingDept"]);
        };
        liste.Add(dept);
    }

    foreach(var nItem in liste)
    {
        listBox3.Items.Add(nItem.ID + " " + nItem.RemainingDept);
    }
}

2。无类方法：

相同的结果，代码少得多。

private void button2_Click(object sender, EventArgs e)
{
    OleDbCommand cmd = new OleDbCommand("SELECT ID, RemainingDept FROM Dept_Tbl ORDER BY RemainingDept", conn);
    OleDbDataReader dr = cmd.ExecuteReader();

    while (dr.Read())
        listBox3.Items.Add(dr["ID"] + " " + dr["RemainingDept"]);
}

Answer 3

使用它。它将数据排序并将两个字段连接在一起。将其转换为列表，然后显示。跳过自定义排序。

OleDbCommand cmd = new OleDbCommand(" SELECT ID || ' ' || RemainingDept FROM Dept_Tbl ORDER BY RemainingDept", conn);

从访问和列表框c＃获取数据

3 个答案:

1。班级方法：

2。无类方法：