Hi rani,

Check this example. Now please take its reference and correct your code.

Database

For this example I have used of Northwind database that you can download using the link given below.

Download Northwind Database

HTML

<script type="text/javascript" src="//ajax.googleapis.com/ajax/libs/angularjs/1.3.9/angular.min.js"></script>
<script type="text/javascript" src="//cdnjs.cloudflare.com/ajax/libs/Chart.js/2.6.0/Chart.bundle.min.js"></script>
<script type="text/javascript">
    var app = angular.module('MyApp', [])
    app.controller('MyController', function ($scope, $http, $window) {
        $http.post("Default.aspx/GetChartData", { headers: { 'Content-Type': 'application/json'} })
        .then(function (response) {
            $scope.ChartData = {
                labels: response.data.d[0],
                data: response.data.d[1],
                color: response.data.d[2]
            };
            var ctx = document.getElementById("dvCanvas").getContext('2d');
            var myChart = new Chart(ctx, {
                type: 'pie',
                data: {
                    datasets: [{
                        data: $scope.ChartData.data,
                        backgroundColor: $scope.ChartData.color
                    }],
                    labels: $scope.ChartData.labels
                },
                options: {
                    responsive: true
                }
            });
        }, function (response) {
            $window.alert(response.responseText);
        });
    });
</script>
<div ng-app="MyApp" ng-controller="MyController">
    <canvas id="dvCanvas" height="300" width="500"></canvas>
</div>

Namespaces

C#

using System.Collections.Generic;
using System.Configuration;
using System.Data;
using System.Data.SqlClient;
using System.Web.Services;

VB.Net

Imports System.Collections.Generic
Imports System.Configuration
Imports System.Data
Imports System.Data.SqlClient
Imports System.Web.Services

Code

C#

[WebMethod]
public static List<object> GetChartData()
{
    List<object> chartData = new List<object>();

    List<string> labels = new List<string>();
    List<int> data = new List<int>();
    List<string> color = new List<string>();

    string query = "SELECT ShipCity,COUNT(OrderId) [Total] FROM Orders WHERE ShipCountry = 'USA' GROUP BY ShipCity";
    DataTable dt = new DataTable();
    string constr = ConfigurationManager.ConnectionStrings["constr"].ConnectionString;
    using (SqlConnection con = new SqlConnection(constr))
    {
        using (SqlCommand cmd = new SqlCommand(query))
        {
            using (SqlDataAdapter sda = new SqlDataAdapter())
            {
                cmd.CommandType = CommandType.Text;
                cmd.Connection = con;
                sda.SelectCommand = cmd;
                sda.Fill(dt);
            }
        }
    }
    foreach (DataRow row in dt.Rows)
    {
        labels.Add(row["ShipCity"].ToString());
        data.Add(Convert.ToInt32(row["Total"]));
        System.Threading.Thread.Sleep(50);
        color.Add(String.Format("#{0:X6}", new Random().Next(0x1000000)));
    }

    chartData.Add(labels.ToArray());
    chartData.Add(data.ToArray());
    chartData.Add(color.ToArray());

    return chartData;
}

VB.Net

<WebMethod()>
Public Shared Function GetChartData() As List(Of Object)
    Dim chartData As List(Of Object) = New List(Of Object)()
    Dim labels As List(Of String) = New List(Of String)()
    Dim data As List(Of Integer) = New List(Of Integer)()
    Dim color As List(Of String) = New List(Of String)()
    Dim query As String = "SELECT ShipCity,COUNT(OrderId) [Total] FROM Orders WHERE ShipCountry = 'USA' GROUP BY ShipCity"
    Dim dt As DataTable = New DataTable()
    Dim constr As String = ConfigurationManager.ConnectionStrings("constr").ConnectionString
    Using con As SqlConnection = New SqlConnection(constr)
        Using cmd As SqlCommand = New SqlCommand(query)
            Using sda As SqlDataAdapter = New SqlDataAdapter()
                cmd.CommandType = CommandType.Text
                cmd.Connection = con
                sda.SelectCommand = cmd
                sda.Fill(dt)
            End Using
        End Using
    End Using
    For Each row As DataRow In dt.Rows
        labels.Add(row("ShipCity").ToString())
        data.Add(Convert.ToInt32(row("Total")))
        System.Threading.Thread.Sleep(50)
        color.Add(String.Format("#{0:X6}", New Random().[Next](&H1000000)))
    Next
    chartData.Add(labels.ToArray())
    chartData.Add(data.ToArray())
    chartData.Add(color.ToArray())

    Return chartData
End Function

Screenshot