Search data from CSV file based on TextBox value using C# and VB.Net in ASP.Net

Hi LessClue,

Refer the below sample code for your reference and implement it in your code as per your logic.

First read the CSV to DataTable and then filter using multiple condition.

CSV File

HTML

Id: <asp:TextBox ID="txtId" runat="server"></asp:TextBox><br />
Name: <asp:TextBox ID="txtName" runat="server"></asp:TextBox><br />
Country: <asp:TextBox ID="txtCountry" runat="server"></asp:TextBox><br />
<asp:Button ID="btnSearch" runat="server" Text="Search" OnClick="OnSearch" />
<hr />
<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="false">
    <Columns>
        <asp:BoundField DataField="Id" HeaderText="Id" />
        <asp:BoundField DataField="Name" HeaderText="Name" />
        <asp:BoundField DataField="Country" HeaderText="Country" />
    </Columns>
</asp:GridView>

Namespaces

C#

using System.Data;

VB.Net

Imports System.Data

Code

C#

protected void OnSearch(object sender, EventArgs e)
{
    string csvPath = Server.MapPath("~/Files/Sample.csv");
    DataTable dt = new DataTable();
    dt.Columns.AddRange(new DataColumn[3] {
    new DataColumn("Id", typeof(string)),
    new DataColumn("Name", typeof(string)),
    new DataColumn("Country",typeof(string)) });
    string csvData = System.IO.File.ReadAllText(csvPath);

    foreach (string row in csvData.Split('\n'))
    {
        if (!string.IsNullOrEmpty(row))
        {
            dt.Rows.Add();
            int i = 0;
            foreach (string cell in row.Split(','))
            {
                dt.Rows[dt.Rows.Count - 1][i] = cell;
                i++;
            }
        }
    }

    IEnumerable<DataRow> result = (from row in dt.AsEnumerable()
                                    where (row["Id"].ToString() == txtId.Text.Trim() || string.IsNullOrEmpty(txtId.Text.Trim()))
                                        && (row["Name"].ToString().ToLower().Contains(txtName.Text.Trim().ToLower()) || string.IsNullOrEmpty(txtName.Text.Trim()))
                                        && (row["Country"].ToString().ToLower().StartsWith(txtCountry.Text.Trim().ToLower()) || string.IsNullOrEmpty(txtCountry.Text.Trim()))
                                    select row).ToList();
    DataTable final = dt.Clone();
    if (result.Count() > 0)
    {
        final = result.CopyToDataTable();
    }

    GridView1.DataSource = final;
    GridView1.DataBind();
}

VB.Net

Protected Sub OnSearch(ByVal sender As Object, ByVal e As EventArgs)
    Dim csvPath As String = Server.MapPath("~/Files/Sample.csv")
    Dim dt As DataTable = New DataTable()
    dt.Columns.AddRange(New DataColumn(2) {
                            New DataColumn("Id", GetType(Integer)),
                            New DataColumn("Name", GetType(String)),
                            New DataColumn("Country", GetType(String))})
    Dim csvData As String = System.IO.File.ReadAllText(csvPath)
    For Each row As String In csvData.Split(vbLf)
        If Not String.IsNullOrEmpty(row) Then
            dt.Rows.Add()
            Dim i As Integer = 0
            For Each cell As String In row.Split(","c)
                dt.Rows(dt.Rows.Count - 1)(i) = cell
                i += 1
            Next
        End If
    Next

    Dim result As IEnumerable(Of DataRow) = (From row In dt.AsEnumerable()
                                             Where (row("Id").ToString() = txtId.Text.Trim() OrElse String.IsNullOrEmpty(txtId.Text.Trim())) _
                                                     AndAlso (row("Name").ToString().ToLower().Contains(txtName.Text.Trim().ToLower()) OrElse String.IsNullOrEmpty(txtName.Text.Trim())) _
                                                     AndAlso (row("Country").ToString().ToLower().StartsWith(txtCountry.Text.Trim().ToLower()) OrElse String.IsNullOrEmpty(txtCountry.Text.Trim()))
                                             Select row).ToList()
    Dim final As DataTable = dt.Clone()
    If result.Count() > 0 Then
        final = result.CopyToDataTable()
    End If

    GridView1.DataSource = final
    GridView1.DataBind()
End Sub