Import (Upload) CSV file data to DataTable using WebService

Here I have created sample that will help you out.

HTML

<div>
    <asp:FileUpload ID="fu1" runat="server" />
    <asp:Button Text="Import" runat="server" OnClick="Import" />
    <br />
    <br />
    <asp:GridView ID="gvData" runat="server" AutoGenerateColumns="true" />
</div>

Code

C#

protected void Import(object sender, EventArgs e)
{
    if (fu1.HasFile)
    {
        string csvPath = Server.MapPath("~/Files/") + Path.GetFileName(fu1.PostedFile.FileName);
        fu1.SaveAs(csvPath);
        ImportService.ImportCSVSoapClient client = new ImportService.ImportCSVSoapClient();
        DataTable dt = client.GetCSVData(csvPath, new string[] { "Id", "Name", "Country" });
        gvData.DataSource = dt;
        gvData.DataBind();
    }
}

VB.Net

Protected Sub Import(ByVal sender As Object, ByVal e As EventArgs)
    If fu1.HasFile Then
        Dim csvPath As String = Server.MapPath("~/Files/") + Path.GetFileName(fu1.PostedFile.FileName)
        fu1.SaveAs(csvPath)
        Dim client As ImportService.ImportCSVSoapClient = New ImportService.ImportCSVSoapClient()
        Dim dt As DataTable = client.GetCSVData(csvPath, New String() {"Id", "Name", "Country"})
        gvData.DataSource = dt
        gvData.DataBind()
    End If
End Sub

ImportCSV (WebService)

C#

[WebMethod]
public DataTable GetCSVData(string filePath, params string[] columnNames)
{
    try
    {
        DataTable dt = new DataTable("ImportCSV");
        foreach (string columnName in columnNames)
        {
            dt.Columns.Add(columnName);
        }
        string csvData = File.ReadAllText(filePath);
        foreach (string row in csvData.Split('\n'))
        {
            if (!string.IsNullOrEmpty(row))
            {
                dt.Rows.Add();

                for (int i = 0; i < columnNames.Length; i++)
                {
                    dt.Rows[dt.Rows.Count - 1][i] = row.Split(',')[i];
                }
            }
        }
        return dt;
    }
    catch (Exception ex)
    {
        throw new Exception(ex.Message);
    }
}

VB.Net

<WebMethod>
Public Function GetCSVData(ByVal filePath As String, ParamArray columnNames As String()) As DataTable
    Try
        Dim dt As DataTable = New DataTable("ImportCSV")
        For Each columnName As String In columnNames
            dt.Columns.Add(columnName)
        Next

        Dim csvData As String = File.ReadAllText(filePath)
        For Each row As String In csvData.Split(vbLf)
            If Not String.IsNullOrEmpty(row) Then
                dt.Rows.Add()
                For i As Integer = 0 To columnNames.Length - 1
                    dt.Rows(dt.Rows.Count - 1)(i) = row.Split(","c)(i)
                Next
            End If
        Next

        Return dt
    Catch ex As Exception
        Throw New Exception(ex.Message)
    End Try
End Function

Sample.csv

Id,Name,Country

1,John Hammond,United States

2,Mudassar Khan,India

3,Suzanne Mathews,France

4,Robert Schidner,Russia

screenshot