Row filter for datatable

Question

i have column its name : Mark and i want to get rows that start with "CB" and remaining text should be numbers
Ex: Rows
CBY1 10 50 ----> false because remaining text Y1 that not all number
CB1 20 100 ----> ok
CB2 30 200 -----> ok
what is row filter for dataview to get the rows thanks.

Answer 1

DataView.RowFilter doesn't support regular expression syntax, but it is possible to do the filtering with Linq and then convert the results back to a DataView if you need to use that type:

DataTable dt = new DataTable("TestTable");

dt.Columns.Add(new DataColumn("Mark", typeof(string)));
dt.Columns.Add(new DataColumn("Value1", typeof(int)));
dt.Columns.Add(new DataColumn("Value2", typeof(int)));

dt.Rows.Add("CBY1", 10, 50);
dt.Rows.Add("CB1", 20, 200);
dt.Rows.Add("CB2", 30, 300);

DataView dv = dt.AsEnumerable()
 .Where(row => Regex.IsMatch((string)row["Mark"], @"^CB\d+$"))
 .AsDataView();

foreach (DataRowView item in dv) {
 Console.WriteLine(item["Mark"] + ", " + item["Value1"] + ", " + item["Value2"]);
}

Answer 2

Taking @P a u l a step farther consider using a BindingSource which means there is zero reason to work with data via a DataGridView cell values. The example below uses @P a u l logic only layered on top of a BindingSource. Also added a primary key as all data should have one.

using System;  
using System.Data;  
using System.Linq;  
using System.Text.RegularExpressions;  
using System.Windows.Forms;  
  
namespace DataTableFilterExample  
{  
    public partial class Form1 : Form  
    {  
        private readonly BindingSource _bindingSource =   
            new BindingSource();  
          
        public Form1()  
        {  
            InitializeComponent();  
            Shown += OnShown;  
        }  
  
        private void OnShown(object sender, EventArgs e)  
        {  
            _bindingSource.DataSource = LoadDataTable();  
            dataGridView1.DataSource = _bindingSource;  
        }  
  
        private void FilterButton_Click(object sender, EventArgs e)  
        {  
            DataTable table =   
                (  
                    from dataRow in ((DataTable)_bindingSource.DataSource).AsEnumerable()   
                    where Regex.IsMatch(dataRow.Field<string>("Mark"), @"^CB\d+$")   
                    select dataRow  
                )  
                .ToArray()  
                .CopyToDataTable();  
              
            table.Columns["id"].ColumnMapping = MappingType.Hidden;  
              
            _bindingSource.DataSource = table;  
              
        }  
  
        private static DataTable LoadDataTable()  
        {  
            var dt = new DataTable();  
  
            dt.Columns.Add(new DataColumn()  
            {  
                ColumnName = "Id",   
                DataType = typeof(int),   
                AutoIncrement = true,   
                AutoIncrementSeed = 1,  
                ColumnMapping = MappingType.Hidden  
            });  
              
            dt.Columns.Add(new DataColumn("Mark", typeof(string)));  
            dt.Columns.Add(new DataColumn("Value1", typeof(int)));  
            dt.Columns.Add(new DataColumn("Value2", typeof(int)));  
  
            dt.Rows.Add(null,"CBY1", 10, 50);  
            dt.Rows.Add(null,"CB1", 20, 200);  
            dt.Rows.Add(null,"CB2", 30, 300);  
              
            return dt;  
        }  
  
        private void CurrentButton_Click(object sender, EventArgs e)  
        {  
            if (_bindingSource.Current != null)  
            {  
                var row = ((DataRowView) _bindingSource.Current).Row;  
  
                MessageBox.Show($"Id:{row.Field<int>("id"),6:D3}\nValue1:{row.Field<int>("Value1"),6:D3}");  
            }  
            else  
            {  
                MessageBox.Show("No current row");  
            }  
        }  
    }  
}