如何動態的設定變數

Question

 請教一下各位大大

我有個table有六個欄位
我想要用下面這樣的方式取得欄位相關屬性
Class1 c1 = new Class1();
DataTable dt = new DataTable();
dt = c1.rsm("select * from userdata");
 
MessageBox.Show(c1.col1); //取得第一個欄位值
萬一我的table欄位有100個 我該如何改寫下面這個class

class Class1
    {       
        public string col1="";
        public string col2="";
        public string col3="";
        public string col4="";
        public string col5="";
        public string col6="";
        public DataTable rsm(string strsql)
         {
            DataTable smdt = new DataTable();
            string strconn = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:\\test.mdb;User Id=admin;Password=;";
            OleDbConnection objconn = new OleDbConnection(strconn);
            objconn.Open();
            OleDbCommand objcmd = new OleDbCommand(strsql, objconn);
            OleDbDataReader dr = objcmd.ExecuteReader();
            smdt = dr.GetSchemaTable();
            dr.Close();
            objconn.Close();
            col1 = smdt.Rows[0][0].ToString();
            col2 = smdt.Rows[1][0].ToString();
            col3 = smdt.Rows[2][0].ToString();
            col4 = smdt.Rows[3][0].ToString();
            col5 = smdt.Rows[4][0].ToString();
            col6 = smdt.Rows[5][0].ToString();
            return smdt;
        }
           public DataSet rds(string strsql)
        {
            DataSet returnds = new DataSet();
            string strconn = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:\\test.mdb;User Id=admin;Password=;";
            OleDbConnection objconn = new OleDbConnection(strconn);
            OleDbDataAdapter objadt = new OleDbDataAdapter(strsql, objconn);
            objadt.Fill(returnds);
            return returnds;
        }

    }

Answer 1

將你的固定宣告的改用集合型態即可
譬如

class Class1

{

private List<string> _cols = new List<string>();

public List<string> Cols

{

get { return this._cols; }

}

...

}

程式就可以用

Class1 c1 = new Class1();

string col1 = c1.Cols[0];

string col2 = c1.Cols[1];

如果是.Net Framework 1.0可以將泛型集合List改用ArrayList取代.

Answer 2

 感謝大大 使用arraylist就可以用了

 class Class2
    {
        public ArrayList ar = new ArrayList();
        public DataTable rsm(string strsql)
         {
            DataTable smdt = new DataTable();
            string strconn = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:\\test.mdb;User Id=admin;Password=;";
            OleDbConnection objconn = new OleDbConnection(strconn);
            objconn.Open();
            OleDbCommand objcmd = new OleDbCommand(strsql, objconn);
            OleDbDataReader dr = objcmd.ExecuteReader();
            smdt = dr.GetSchemaTable();
            dr.Close();
            objconn.Close();
            for (int i = 0; i < smdt.Rows.Count; i++)
            {
                ar.Add(smdt.Rows[i][0].ToString());
            }
            return smdt;
        }
    }

Answer 3

 DataTable dt  應該有包含欄位資訊

Columns

取得屬於這個資料表的資料行集合

        public string col1="";
        public string col2="";
        public string col3="";
        public string col4="";
        public string col5="";
        public string col6="";

或 public ArrayList ar = new ArrayList(); 

應該無存在的意義.

foreach(DataColumn column in table.Columns)
        {
            Console.WriteLine(row[column]);
        }