asked on

dataset.fieldbyname().asstring

In Delphi, you use dataset to run a query, like select * from atable.
then you can use dataset.fieldbyname('AFieldName').asString (or as DateTime etc.) to get the field's value.

But I find in C#, you can only use fields' index to get the value rather than using field's name. So if you change your select fields order or insert a new field in the select, you have to chnage a lot of statements.

Is there a way use field's name like Delphi in C#?

tomasX2

dataSet.Tables[0].Rows[nRowNumber]["ColumnName"].ToString();

Realmrat

string connectionString = "my conn string";

string commandString = "SELECT * FROM mytable";

OdbcDataAdapter adapter = new OdbcDataAdapter(commandString,connectionString);

DataSet data = new DataSet();
adapter.Fill (data);

// Loop for each record in the dataset
foreach( DataRow row in data.Tables[0].Rows )
{
mycombobox.Items.Add( row["myColumnName"] );
}

Puts all the fields into a dropdown box. Dunno if that helps any. =] Same thing as above almost.

- Joe

petershaw8

ASKER

For tomasX2 solution, I am not sure if it works for a little bit complicated sql statement, like
select a.aCol1,
b.bCol1,
(select cCol2 from cTablen where cCol1 = aCol1) as cCol2
from aTable a, bTable b

In this case, I guess dataSet.Tables[0] regers aTable, dataSet.Tables[1] refers bTable, but how about cCol2?

For Joe's solution, Does the row["myColumnName"] always returns a string? and if the field is type of DateTime, then you need convert it fromstring to datetime?

Peter

Realmrat

The row[index] returns an object, so you can cast it to it's original value.

- Joe

Realmrat

Here's a little form in ASP.NET you can test with. Shows how to interact with object values from the row[index] feature ... I was bored. =]

- Joe

Page:
|-------------------------------------------------------------------------------------------------------------

<%@ Page language="c#" Codebehind="WebForm1.aspx.cs" AutoEventWireup="false" Inherits="EE.WebForm1" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" >
<HTML>
<HEAD>
<title>WebForm1</title>
<meta content="Microsoft Visual Studio .NET 7.1" name="GENERATOR">
<meta content="C#" name="CODE_LANGUAGE">
<meta content="JavaScript" name="vs_defaultClientScript">
<meta content="http://schemas.microsoft.com/intellisense/ie5" name="vs_targetSchema">
</HEAD>
<body>
<form id="Form1" method="post" runat="server">
<table align="center">
<tr>
<td><asp:datagrid id="DataGrid1" runat="server" Width="100%"></asp:datagrid></td>
</tr>
<tr>
<td align="center"><asp:button id="GetDateButton" runat="server" Text="Get Long Date"></asp:button><asp:button id="GetTimeButton" runat="server" Text="Get Short Time"></asp:button></td>
</tr>
<tr>
<td><br>
<br>
<asp:Label id="MessageLabel" runat="server" Font-Bold="True"></asp:Label>
<br>
<asp:DropDownList id="DropDownList1" runat="server"></asp:DropDownList></td>
</tr>
</table>
</form>
</body>
</HTML>

Code:
|-------------------------------------------------------------------------------------------------------------

using System;
using System.Collections;
using System.ComponentModel;
using System.Data;
using System.Data.Odbc;
using System.Data.SqlTypes;
using System.Drawing;
using System.Web;
using System.Web.SessionState;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;

namespace EE
{
      /// <summary>
      /// Summary description for WebForm1.
      /// </summary>
      public class WebForm1 : System.Web.UI.Page
      {
protected DataTable data;
protected System.Web.UI.WebControls.DataGrid DataGrid1;
protected System.Web.UI.WebControls.Button GetDateButton;
protected System.Web.UI.WebControls.Label MessageLabel;
protected System.Web.UI.WebControls.DropDownList DropDownList1;
protected System.Web.UI.WebControls.Button GetTimeButton;
protected DataView dataView;
            private void Page_Load(object sender, System.EventArgs e)
            {
if (Session["TestData"] == null)
{
BuildTable();
}
else
data = (DataTable)Session["TestData"];

dataView = new DataView(data);
dataView.Sort = "Item";
if (!IsPostBack)
BindList();
            }

private void BindList()
{
DataGrid1.DataSource = dataView;
DataGrid1.DataBind();
}

private void BuildTable()
{

data = new DataTable();
data.Columns.Add(new DataColumn("Qty", typeof(string)));
data.Columns.Add(new DataColumn("Item", typeof(string)));
data.Columns.Add(new DataColumn("Price", typeof(string)));
// Can also Use OdbcType.DateTime, SqlDateTime, etc
data.Columns.Add(new DataColumn("Date", typeof(DateTime)));
Session["DL3_ShoppingCart"] = data;

// first load -- prepopulate with some data
for (int i=1; i<5; i++)
{
DataRow dr = data.NewRow();
dr[0] = ((int)((i%2)+1)).ToString();
dr[1] = "Item " + i.ToString();
dr[2] = ((double)(1.23 * (i+1))).ToString();
dr[3] = DateTime.Now.AddDays((int)(2*(i+30)));
data.Rows.Add(dr);
}
}

            #region Web Form Designer generated code
            override protected void OnInit(EventArgs e)
            {
                  //
                  // CODEGEN: This call is required by the ASP.NET Web Form Designer.
                  //
                  InitializeComponent();
                  base.OnInit(e);
            }

            /// <summary>
            /// Required method for Designer support - do not modify
            /// the contents of this method with the code editor.
            /// </summary>
            private void InitializeComponent()
            {
this.GetDateButton.Click += new System.EventHandler(this.GetDateButton_Click);
this.GetTimeButton.Click += new System.EventHandler(this.GetTimeButton_Click);
this.Load += new System.EventHandler(this.Page_Load);

}
            #endregion

private void GetDateButton_Click(object sender, System.EventArgs e)
{
try
{
foreach(DataRow row in data.Rows)
{
DateTime myDate = (DateTime) row["date"];
DropDownList1.Items.Add(myDate.ToLongDateString());
}
}
catch(Exception exc)
{
MessageLabel.Text = exc.Message;
}
}

private void GetTimeButton_Click(object sender, System.EventArgs e)
{
try
{
foreach(DataRow row in data.Rows)
{
DateTime myDate = (DateTime) row["date"];
DropDownList1.Items.Add(myDate.ToShortTimeString());
}
}
catch(Exception exc)
{
MessageLabel.Text = exc.Message;
}
}
      }
}

ASKER CERTIFIED SOLUTION

Realmrat

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