Solved

dataset expression

Posted on 2014-03-01
3
550 Views
Last Modified: 2014-03-02
i want defin function by visual studio 2010 to make some thing and call this function in dataset by DataColumn proprieties  ---> expression : myfunction ()
dataset
0
Comment
Question by:mahmuod
  • 2
3 Comments
 
LVL 13

Expert Comment

by:Naman Goel
ID: 39897220
Not possible. The expression parser behind the Expression property is simple and not extensible. Making arbitrary function calls is not one of its capabilities. There are several ways to work around this, especially ones that don't require an expensive reflection lookup. Consider the DataTable.RowChanged event for example.
0
 

Author Comment

by:mahmuod
ID: 39897593
Thank u
But how to make same  by anther way
For example
I want datacolumn to calculate datediff between to date i have function but i can insert it to datacolumn
0
 
LVL 13

Accepted Solution

by:
Naman Goel earned 500 total points
ID: 39898855
Here is sample code for that:
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        private DataGridView dataGridView1;
        private Button button1;
        private DataTable dataTable = null;
        public Form1()
        {
            InitializeComponent();
            InitializeDataTable();
        }

        private void InitializeDataTable()
        {
            dataTable = new DataTable();
            DataColumn colFromDate = new DataColumn("FromDate", typeof(DateTime));
            DataColumn colToDate = new DataColumn("ToDate", typeof(DateTime));
            DataColumn colDateDiff = new DataColumn("DateDiff", typeof(string));
            dataTable.Columns.AddRange(new DataColumn[] { colFromDate, colToDate, colDateDiff });
            dataTable.RowChanged += dataTable_RowChanged;

            for (int i = 0; i < 10; i++)
            {
                DateTime fromDate=DateTime.Now.AddYears(i);
                DateTime toDate= fromDate.AddDays(i);
                dataTable.Rows.Add(fromDate, toDate);
            }
        }


        void dataTable_RowChanged(object sender, DataRowChangeEventArgs e)
        {
            if (e.Action == DataRowAction.Add)
            {
                e.Row["DateDiff"] = String.Format("{0} Days", Convert.ToDateTime(e.Row["ToDate"]) - Convert.ToDateTime(e.Row["FromDate"]));
            }

        }

        private void InitializeComponent()
        {
            this.dataGridView1 = new System.Windows.Forms.DataGridView();
            this.button1 = new System.Windows.Forms.Button();
            ((System.ComponentModel.ISupportInitialize)(this.dataGridView1)).BeginInit();
            this.SuspendLayout();
            // 
            // dataGridView1
            // 
            this.dataGridView1.ColumnHeadersHeightSizeMode = System.Windows.Forms.DataGridViewColumnHeadersHeightSizeMode.AutoSize;
            this.dataGridView1.Location = new System.Drawing.Point(25, 12);
            this.dataGridView1.Name = "dataGridView1";
            this.dataGridView1.Size = new System.Drawing.Size(240, 150);
            this.dataGridView1.TabIndex = 0;
            // 
            // button1
            // 
            this.button1.Location = new System.Drawing.Point(34, 189);
            this.button1.Name = "button1";
            this.button1.Size = new System.Drawing.Size(75, 23);
            this.button1.TabIndex = 1;
            this.button1.Text = "button1";
            this.button1.UseVisualStyleBackColor = true;
            this.button1.Click += new System.EventHandler(this.button1_Click);
            // 
            // Form1
            // 
            this.ClientSize = new System.Drawing.Size(292, 273);
            this.Controls.Add(this.button1);
            this.Controls.Add(this.dataGridView1);
            this.Name = "Form1";
            ((System.ComponentModel.ISupportInitialize)(this.dataGridView1)).EndInit();
            this.ResumeLayout(false);

        }

        private void button1_Click(object sender, EventArgs e)
        {
            dataGridView1.DataSource = null;
            dataGridView1.DataSource = dataTable;
        }
    }
}

Open in new window

0

Featured Post

Microsoft Certification Exam 74-409

Veeam® is happy to provide the Microsoft community with a study guide prepared by MVP and MCT, Orin Thomas. This guide will take you through each of the exam objectives, helping you to prepare for and pass the examination.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

A long time ago (May 2011), I have written an article showing you how to create a DLL using Visual Studio 2005 to be hosted in SQL Server 2005. That was valid at that time and it is still valid if you are still using these versions. You can still re…
Real-time is more about the business, not the technology. In day-to-day life, to make real-time decisions like buying or investing, business needs the latest information(e.g. Gold Rate/Stock Rate). Unlike traditional days, you need not wait for a fe…
Familiarize people with the process of retrieving data from SQL Server using an Access pass-thru query. Microsoft Access is a very powerful client/server development tool. One of the ways that you can retrieve data from a SQL Server is by using a pa…
Via a live example, show how to set up a backup for SQL Server using a Maintenance Plan and how to schedule the job into SQL Server Agent.

920 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

15 Experts available now in Live!

Get 1:1 Help Now