如何提取查询出来的值

Question

sql = "select ParentId from Tab_System_Area where AreaId=" + Aid +"";各位大侠 如果 我要用到 ParentId 应该怎样提取出来 .. 麻烦给出详细的代码!
谢谢!

Answer 1

你返回的是啥啊？  
如果是一个DataTabledt.Rows[0]["ParentId"].ToString()

Answer 2

public string connectionString = "server=10.66.66.16;database=db;uid=sa;pwd=aa";
public static DataSet Query(string SQLString)
        {
            using (SqlConnection connection = new SqlConnection(connectionString))
            {
                DataSet ds = new DataSet();
                try
                {
                    connection.Open();
                    SqlDataAdapter command = new SqlDataAdapter(SQLString, connection);
                    command.Fill(ds, "ds");
                }
                catch (System.Data.SqlClient.SqlException ex)
                {
                    throw new Exception(ex.Message);
                }
                return ds;
            }
        }
string sql = "select ParentId from Tab_System_Area where AreaId=" + Aid +""; 
dataset ds=Query(sql);
string id= ds.datatables[0].rows[0]["ParentId"].tostring();改大小写

Answer 3

这不查出来了吗~
SqlConnection con = new Sqlconnection(connectionstring);
SqlCommand com = new SqlCommand(con,sql);
SqlReader reader = com.ExecuteReader();
reader里面就读出来了

Answer 4

try
                {
                    sql = "select ParentId from Tab_System_Area where AreaId=" + Aid +"";                     SqlCommand cmd=new SqlCommand(sql,conn);
                    cmd.Connecction.Open();
                    SqlDataReader reader = cmd.ExecuteReader();
                     
                    if (reader.Read())
                    {
                     int id = (int)reader["ParentId "];
                      
                    }
                    reader.Close();                }
                catch (Exception ex)
                {
                    Logger.LogException(LogComponentConstants.SQLServer, ex.Message);
                }
                finally
                {
                    try
                    {
                        conn.Close();
                    }
                    catch { }
                }

Answer 5

 protected void Button1_Click(object sender, EventArgs e)
    {
        string sql;        string Aid = this.TreeView1.SelectedValue;        string Areaname = this.TextBox1.Text;        sql = "select ParentId from Tab_System_Area where AreaId=" + Aid +"";        DataTable DT = new DataTable();        DT = ReadData(sql);        int pid = Convert.ToInt32(DT.Rows[0]["ParentId"]);
    
        sql = "insert into Tab_System_Area values('"+ Areaname +"',"+ pid +")";        dfun.ExecSQLDataResult(sql);        this.TextBox1.Text = null;        TreeView1.Nodes.Clear();
        
        CreateNode("0", (TreeNode)null);        TreeView1.ExpandAll();
    }
datatable类:
 private DataTable ReadData(string sql)
    {
        DataSet ds = dfun.ExecSQLDataSet("select * from Tab_System_Area");        dt = ds.Tables[0];        this.TreeView1.DataBind();        return dt;
    }这样对吗?? 可是还是不行啊