In this article I will explain with an example, how to select the data from database using Dapper library in ASP.Net using C# and VB.Net.
 
 

Installing Dapper package using Nuget

In order to install Dapper library using Nuget, please refer my article Install Dapper from Nuget in Visual Studio.
 
 

Database

I have made use of the following table Customers with the schema as follows.
Select using Dapper in ASP.Net
 
I have already inserted few records in the table.
Select using Dapper in ASP.Net
 
Note: You can download the database table SQL by clicking the download link below.
          Download SQL file
 
 

HTML Markup

The HTML Markup consists of:
GridView – For displaying data.
The GridView consists of three BoundField columns.
<asp:GridView ID="gvCustomers" runat="server" AutoGenerateColumns="false">
    <Columns>
        <asp:BoundField DataField="CustomerId" HeaderText="Customer Id" />
        <asp:BoundField DataField="Name" HeaderText="Name" />
        <asp:BoundField DataField="Country" HeaderText="Country" />
    </Columns>
</asp:GridView>
 
 

Namespaces

You will need to import the following namespaces.
C#
using Dapper;
using System.Data;
using System.Data.SqlClient;
using System.Configuration;
 
VB.Net
Imports Dapper
Imports System.Data
Imports System.Data.SqlClient
Imports System.Configuration
 
 

Selecting using Dapper in ASP.Net

Inside the Page_Load event handler, the records are fetched from the Customers Table of SQL Server database using ExecuteReader method of Dapper library and copied to DataTable object using Load method.
Note: For more details on how to use ExecuteReader, please refer my article Understanding Dapper ExecuteReader in C# and VB.Net
 
Finally, the DataTable is assigned to the DataSource property of GridView and DataBind method is called.
C#
protected void Page_Load(object sender, EventArgs e)
{
    if (!this.IsPostBack)
    {
        string sql = "SELECT CustomerId, Name, Country FROM Customers";
        string constr = ConfigurationManager.ConnectionStrings["constr"].ConnectionString;
        using (SqlConnection con = new SqlConnection(constr))
        {
            using (IDataReader sdr = con.ExecuteReader(sql))
            {
                using (DataTable dtCustomers = new DataTable())
                {
                    dtCustomers.Load(sdr);
                    gvCustomers.DataSource = dtCustomers;
                    gvCustomers.DataBind();
                }
            }
        }
    }
}
 
VB.Net
Protected Sub Page_Load(sender As Object, ByVal e As EventArgs) Handles Me.Load
    If Not Me.IsPostBack Then
        Dim sql As String = "SELECT CustomerId, Name, Country FROM Customers"
        Dim constr As String = ConfigurationManager.ConnectionStrings("constr").ConnectionString
        Using con As SqlConnection = New SqlConnection(constr)
            Using sdr As IDataReader = con.ExecuteReader(sql)
                Using dtCustomers As DataTable = New DataTable()
                    dtCustomers.Load(sdr)
                    gvCustomers.DataSource = dtCustomers
                    gvCustomers.DataBind()
                End Using
            End Using
        End Using
    End If
End Sub
 
 

Screenshot

Select using Dapper in ASP.Net
 
 

Downloads

Download Code