Count number of rows in Linq query result using C# and VB.Net in Console Application

Hi ahmedsa,

Convert the result to List then you can use Count function.

Refer below sample code.

Namespaces

C#

using System.Data;

VB.Net

Imports System.Data

Code

C#

static void Main(string[] args)
{
    DataTable dataTable = GetData();

    var res = from row in dataTable.AsEnumerable()
                group row by row["Files"] into g
                select g;

    if (res.ToList().Count == 1)
    {
        // Do your Task.
    }
    else
    {
        // Do your Task.
    }
}

public static DataTable GetData()
{
    DataTable dataTable = new DataTable();
    dataTable.Columns.Add("PartId", typeof(int));
    dataTable.Columns.Add("Company", typeof(string));
    dataTable.Columns.Add("Files", typeof(string));
    dataTable.Columns.Add("Tab", typeof(string));
    dataTable.Columns.Add("Module", typeof(int));
    dataTable.Rows.Add(1222, "micro", "Abc", "source", 1);
    dataTable.Rows.Add(1321, "silicon", "Abc", "Types", 3);
    dataTable.Rows.Add(1444, "cd2", "AutoD", "Rev", 10);
    dataTable.Rows.Add(1321, "cd3", "AutoD", "source", 11);
    dataTable.Rows.Add(1541, "mtvscro", "AutoD", "Rev", 12);
    dataTable.Rows.Add(9811, "tvs2", "Mog", "Dal", 6);
    dataTable.Rows.Add(1901, "tvs3", "Mog", "Mondo", 6);
    dataTable.Rows.Add(2111, "toyo", "Mog", "Pingo", 7);

    return dataTable;
}

VB.Net

Sub Main()
    Dim dataTable As DataTable = GetData()
    Dim res = From row In dataTable.AsEnumerable()
                Group row By key = row("Files") Into Group
                Select Group
    If res.ToList().Count = 1 Then
        ' Do your Task.
    Else
        ' Do your Task.
    End If
End Sub
Public Function GetData() As DataTable
    Dim dataTable As DataTable = New DataTable()
    dataTable.Columns.Add("PartId", GetType(Integer))
    dataTable.Columns.Add("Company", GetType(String))
    dataTable.Columns.Add("Files", GetType(String))
    dataTable.Columns.Add("Tab", GetType(String))
    dataTable.Columns.Add("Module", GetType(Integer))
    dataTable.Rows.Add(1222, "micro", "Abc", "source", 1)
    dataTable.Rows.Add(1321, "silicon", "Abc", "Types", 3)
    dataTable.Rows.Add(1444, "cd2", "AutoD", "Rev", 10)
    dataTable.Rows.Add(1321, "cd3", "AutoD", "source", 11)
    dataTable.Rows.Add(1541, "mtvscro", "AutoD", "Rev", 12)
    dataTable.Rows.Add(9811, "tvs2", "Mog", "Dal", 6)
    dataTable.Rows.Add(1901, "tvs3", "Mog", "Mondo", 6)
    dataTable.Rows.Add(2111, "toyo", "Mog", "Pingo", 7)
    Return dataTable
End Function