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Friday 21 March 2014

How to Allow / Disallow search engines to crawl using a robots.txt

How to Allow / Disallow search engines to crawl using a robots.txt
Robots.txt is a file placed in our websites root directory and its used to instruct search engines which files or folders allowed to crawl and which is restricted, in this tutorial I will show you how to create a robots.txt file and some of its commands to allow and disallow search engine crawlers to view. All the search engines follow your robots.txt file instruction and allowed to index pages allowed by your robots.txt file.


Search engine come on your website and check your robots.txt first and then goto allowed directories pages never visit any restricted area.
Syntax to allow:
User-agent: *
Allow: /
This means search engines allowed to crawl your complete site.
Syntax to disallow:
User-agent: *
Disallow:  /
Now search engine will not crawl your website and not index any thing.
When you search a disallowed website on google it shows something like this see image below.


Disallow particular folder:
User-agent: *
Disallow:  /wp-admin/
Disallow:  /wp-includes/

Above commands disallow only 2 given folders to all search engines.
Disallow particular file:

User-agent: *
Disallow:  /includes/db.php

Now search engines forced to ignore db.php file to index.
Robots meta:
You can also disallow robots to index files using meta tags in your website.

<meta name="robots" content="noindex">

As we all know that meta is machine parsable not displayed on pages so this meta give instruction to search engine robots.
Disallow / allow particular search engine bot to crawl:
Robots.txt file allow you to give crawling rights to your favorite search engine bots and disallow others by search engine bot name complete and up to date search engines bot list available here.
User-agent: Googlebot
Disallow: /
Using this command you are disallowing Googlebot to crawl and index your website.


Insert, Delete, Update in GridView in ASP.Net using C#

ASP.NET GridView is a very common and useful control. Here, I’m explaining how to work with GridView control in ASP.NET, like how to insert, delete and update record in GridView control. Follow bellow steps to know how to work with GridView in ASP.NET.
Step 1:- Create Database in SqlServer and create a table within this database. For demonstration here I have created database named “Demo” and table named “GridView”
CREATE DATABASE DEMO
GO
USE DEMO
GO
CREATE TABLE GridView
(
id INT PRIMARY KEY IDENTITY,
name VARCHAR (50) NOT NULL,
age INT NOT NULL,
salary FLOAT NOT NULL,
country VARCHAR(50) NOT NULL,
city VARCHAR(50) NOT NULL,
photopath VARCHAR(500) NULL
)
GO
 
Insert, Delete, Update in GridView in ASP.Net using C#
Note: Here “id” column is auto increment and primary key. 
Step 2:- Add connection string in your application’s web.config file and change name and connectionString according your SQL Server configuration as following.
<configuration>
     <connectionStrings>
                <add name="dbconnection" providerName="System.Data.SqlClient"
                    connectionString="Data Source=.;Initial Catalog=demo; User Id=xyz; password=123456" />
                </connectionStrings>
</configuration>
Step 3:- Drag & drop GridView control from Toolbox on “.aspx” page and write down the following line of code within <asp:GridView> section or simple copy the following line of code and put where you want to display GridVIew.
<div>
        <asp:GridView ID="GridView1" runat="server" ShowHeaderWhenEmpty="True"
            AutoGenerateColumns="False" onrowdeleting="RowDeleting"
            OnRowCancelingEdit="cancelRecord" OnRowEditing="editRecord"
            OnRowUpdating="updateRecord" CellPadding="4"
            EnableModelValidation="True" GridLines="None" Width="1297px"
            ForeColor="#333333" >
            <RowStyle HorizontalAlign="Center" />
            <AlternatingRowStyle BackColor="White" />
            <EditRowStyle BackColor="#7C6F57" />
            <FooterStyle BackColor="#1C5E55" ForeColor="White" Font-Bold="True" />
            <HeaderStyle BackColor="#1C5E55" Font-Bold="True" ForeColor="White" />
            <PagerStyle BackColor="#666666" ForeColor="White" HorizontalAlign="Center" />
            <RowStyle BackColor="#E3EAEB" />
            <SelectedRowStyle BackColor="#C5BBAF" Font-Bold="True" ForeColor="#333333" />
            <Columns>
            <asp:TemplateField>
            <HeaderTemplate>Id</HeaderTemplate>
            <ItemTemplate>
            <asp:Label ID ="lblId" runat="server" Text='<%#Bind("id")%>'></asp:Label>
            </ItemTemplate>
            </asp:TemplateField>
            <asp:TemplateField>
            <HeaderTemplate>Name</HeaderTemplate>
            <ItemTemplate>
            <asp:Label ID ="lblName" runat="server" Text='<%#Bind("name") %>'></asp:Label>
            </ItemTemplate>
            <EditItemTemplate>
            <asp:TextBox ID="txtName" runat="server" Text='<%#Bind("name") %>' MaxLength="50"></asp:TextBox>
            <asp:RequiredFieldValidator ID="rfvtxtName" runat="server" Text="*" ToolTip="Enter name" ControlToValidate="txtName"></asp:RequiredFieldValidator>
            <asp:RegularExpressionValidator ID="revtxtName" runat="server" Text="*" ToolTip="Enter alphabate " ControlToValidate="txtName" ValidationExpression="^[a-zA-Z'.\s]{1,40}$"></asp:RegularExpressionValidator>
           
            </EditItemTemplate>
            <FooterTemplate>
            <asp:TextBox ID="txtNewName" runat="server" MaxLength="50"></asp:TextBox>
            <asp:RequiredFieldValidator ID="rfvtxtNewName" runat="server" Text="*" ToolTip="Enter name" ControlToValidate="txtNewName"></asp:RequiredFieldValidator>
            <asp:RegularExpressionValidator ID="revtxtNewName" runat="server" Text="*" ToolTip="Enter alphabate " ControlToValidate="txtNewName" ValidationExpression="^[a-zA-Z'.\s]{1,40}$"></asp:RegularExpressionValidator>
          
            </FooterTemplate>
            </asp:TemplateField>
           
            <asp:TemplateField>
            <HeaderTemplate>Age</HeaderTemplate>
            <ItemTemplate>
            <asp:Label ID="lblAge" runat ="server" Text='<%#Bind("age") %>'></asp:Label>
            </ItemTemplate>
            <EditItemTemplate>
            <asp:TextBox ID ="txtAge" runat="server" Text='<%#Bind("age") %>' MaxLength="2"></asp:TextBox>
            <asp:RequiredFieldValidator ID="rfvtxtAge" runat="server" Text="*" ToolTip="Enter age" ControlToValidate="txtAge"></asp:RequiredFieldValidator>
            <asp:RegularExpressionValidator ID="revtxtAge" runat="server" Text="*" ToolTip="Enter numeric value" ControlToValidate="txtAge" ValidationExpression="^[0-9]+$"></asp:RegularExpressionValidator>
          
            </EditItemTemplate>
            <FooterTemplate>
            <asp:TextBox ID="txtNewAge" runat="server" MaxLength="2"></asp:TextBox>
            <asp:RequiredFieldValidator ID="rfvtxtNewAge" runat="server" Text="*" ToolTip="Enter age" ControlToValidate="txtNewAge"></asp:RequiredFieldValidator>
            <asp:RegularExpressionValidator ID="revNewtxtAge" runat="server" Text="*" ToolTip="Enter numeric value" ControlToValidate="txtNewAge" ValidationExpression="^[0-9]+$"></asp:RegularExpressionValidator>
            </FooterTemplate>
            </asp:TemplateField>
            <asp:TemplateField>
            <HeaderTemplate>Salary</HeaderTemplate>
            <ItemTemplate>
            <asp:Label ID = "lblSalary" runat="server" Text='<%#Bind("salary") %>'></asp:Label>
            </ItemTemplate>
            <EditItemTemplate>
            <asp:TextBox ID="txtSalary" runat="server" Text='<%#Bind("salary") %>'  MaxLength="10"></asp:TextBox>
            <asp:RequiredFieldValidator ID="rfvtxtSalary" runat="server" Text="*"  ToolTip="Enter salary" ControlToValidate="txtSalary"></asp:RequiredFieldValidator>
            <asp:RegularExpressionValidator ID="revtxtSalary" runat="server" Text="*" ToolTip="Enter numeric value" ControlToValidate="txtSalary" ValidationExpression="^[0-9]+$"></asp:RegularExpressionValidator>
          
            </EditItemTemplate>
            <FooterTemplate>
            <asp:TextBox ID="txtNewSalary" runat="server" MaxLength="10"></asp:TextBox>
            <asp:RequiredFieldValidator ID="rfvtxtNewSalary" runat="server" Text="*"  ToolTip="Enter salary" ControlToValidate="txtNewSalary"></asp:RequiredFieldValidator>
            <asp:RegularExpressionValidator ID="revtxtNewSalary" runat="server" Text="*" ToolTip="Enter numeric value" ControlToValidate="txtNewSalary" ValidationExpression="^[0-9]+$"></asp:RegularExpressionValidator>
            </FooterTemplate>
            </asp:TemplateField>
            <asp:TemplateField>
            <HeaderTemplate>Country</HeaderTemplate>
            <ItemTemplate>
            <asp:Label ID = "lblCountry" runat="server" Text='<%#Bind("country") %>'></asp:Label>
            </ItemTemplate>
            <EditItemTemplate>
            <asp:TextBox ID="txtCountry" runat="server" Text='<%#Bind("country") %>' MaxLength="20"></asp:TextBox>
            <asp:RequiredFieldValidator ID="rfvtxtCountry" runat="server" Text="*" ToolTip="Enter country" ControlToValidate="txtCountry"></asp:RequiredFieldValidator>
        
            </EditItemTemplate>
            <FooterTemplate>
            <asp:TextBox ID="txtNewCountry" runat="server" MaxLength="20"></asp:TextBox>
            <asp:RequiredFieldValidator ID="rfvtxtNewCountry" runat="server" Text="*" ToolTip="Enter country" ControlToValidate="txtNewCountry"></asp:RequiredFieldValidator>
            </FooterTemplate>
            </asp:TemplateField>
            <asp:TemplateField>
            <HeaderTemplate>City</HeaderTemplate>
            <ItemTemplate>
            <asp:Label ID = "lblCity" runat="server" Text='<%#Bind("city") %>'></asp:Label>
            </ItemTemplate>
            <EditItemTemplate>
            <asp:TextBox ID="txtCity" runat="server" Text='<%#Bind("city") %>' MaxLength="20"></asp:TextBox>
            <asp:RequiredFieldValidator ID="rfvtxtCity" runat="server" Text="*" ToolTip="Enter city" ControlToValidate="txtCity"></asp:RequiredFieldValidator>
            </EditItemTemplate>
            <FooterTemplate>
            <asp:TextBox ID="txtNewCity" runat="server" MaxLength="20"></asp:TextBox>
            <asp:RequiredFieldValidator ID="rfvtxtNewCity" runat="server" Text="*" ToolTip="Enter city" ControlToValidate="txtNewCity"></asp:RequiredFieldValidator>
            </FooterTemplate>
            </asp:TemplateField>
            <asp:TemplateField>
            <HeaderTemplate>Photo</HeaderTemplate>
            <ItemTemplate>
            <asp:Image ID="imgPhoto" Width="100px" Height="100px" runat="server" text="Photo" ImageUrl='<%#Bind("photopath") %>' />
            </ItemTemplate>
            <EditItemTemplate>
            <asp:FileUpload ID="fuPhoto" runat="server" ToolTip="select Employee Photo"/>
            <asp:RegularExpressionValidator ID="revfuPhoto" runat="server" Text="*" ToolTip="Image formate only" ControlToValidate="fuPhoto" ValidationExpression="[a-zA-Z0_9].*\b(.jpeg|.JPEG|.jpg|.JPG|.jpe|.JPE|.png|.PNG|.mpp|.MPP|.gif|.GIF)\b"></asp:RegularExpressionValidator>
            </EditItemTemplate>
            <FooterTemplate>
            <asp:FileUpload ID="fuNewPhoto" runat="server" ToolTip="select Employee Photo"/>
            <asp:RequiredFieldValidator ID="rfvfuNewPhoto" runat="server" ErrorMessage="*" ToolTip="Select Photo" ControlToValidate="fuNewPhoto"></asp:RequiredFieldValidator>
            <asp:RegularExpressionValidator ID="revfuNewPhoto" runat="server" Text="*" ToolTip="Image formate only" ControlToValidate="fuNewPhoto" ValidationExpression="[a-zA-Z0_9].*\b(.jpeg|.JPEG|.jpg|.JPG|.jpe|.JPE|.png|.PNG|.mpp|.MPP|.gif|.GIF)\b"></asp:RegularExpressionValidator>
            </FooterTemplate>
            </asp:TemplateField>
            <asp:TemplateField>
            <HeaderTemplate>Operation</HeaderTemplate>
            <ItemTemplate>
            <asp:Button ID="btnEdit" runat="server" CommandName="Edit" Text="Edit" />
            <asp:Button ID="btnDelete" runat="server" CommandName="Delete" Text="Delete" CausesValidation="true" OnClientClick="return confirm('Are you sure?')" />
            </ItemTemplate>
            <EditItemTemplate>
            <asp:Button ID="btnUpdate" runat="server" CommandName="Update" Text="Update" />
            <asp:Button ID="btnCancel" runat="server" CommandName="Cancel" Text="Cancel" CausesValidation="false" />
            </EditItemTemplate>
            <FooterTemplate>
            <asp:Button ID="btnNewInsert" runat="server" Text="Insert" OnClick="InsertNewRecord"/>
            <asp:Button ID="btnNewCancel" runat="server" Text="Cancel" OnClick="AddNewCancel" CausesValidation="false" />
            </FooterTemplate>        
            </asp:TemplateField>           
            </Columns>
            <EmptyDataTemplate>
                      No record available                    
            </EmptyDataTemplate>       
        </asp:GridView>
        <br />
        <asp:Button ID="btnAdd" runat="server" Text="Add New Record" OnClick="AddNewRecord" />  
    </div>
 
Step 4:- Create one class within App_Code folder. Here I have given this class named is GlobalClass and write following line of code.
using System.Data;
using System.Data.SqlClient;
public class GlobalClass
{
    public static SqlDataAdapter adap;
    public static DataTable dt;
    // Stored image path before updating the record
    public static string imgEditPath;
}
 
Step 5:- Create one folder, named Images, where we have stored employees photos see in following image.
Insert, Delete, Update in GridView in ASP.Net using C#
Step 6:- Write down following line of code in “.cspage which related to your .aspx page (e.g. if your .aspx page name is default.aspx then your .cs file is default.aspx.cs).
using System;
using System.Data;
using System.Data.SqlClient;
using System.Configuration;
using System.Web.UI.WebControls;
using System.IO;
public partial class _Default : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            // Call FillGridView Method
            FillGridView();
        }
    }
    /// <summary>
    /// Fill record into GridView
    /// </summary>
    public void FillGridView()
    {
        try
        {
            string cnString = ConfigurationManager.ConnectionStrings["dbconnection"].ConnectionString;
            SqlConnection con = new SqlConnection(cnString);
            GlobalClass.adap = new SqlDataAdapter("select * from gridview", con);
            SqlCommandBuilder bui = new SqlCommandBuilder(GlobalClass.adap);
            GlobalClass.dt = new DataTable();
            GlobalClass.adap.Fill(GlobalClass.dt);
            GridView1.DataSource = GlobalClass.dt;
            GridView1.DataBind();
        }
        catch
        {
            Response.Write("<script> alert('Connection String Error...') </script>");
        }
    }
    /// <summary>
    /// Edit record
    /// </summary>
    /// <param name="sender"></param>
    /// <param name="e"></param>
    protected void editRecord(object sender, GridViewEditEventArgs e)
    {
        // Get the image path for remove old image after update record
        Image imgEditPhoto = GridView1.Rows[e.NewEditIndex].FindControl("imgPhoto") as Image;
        GlobalClass.imgEditPath = imgEditPhoto.ImageUrl;
        // Get the current row index for edit record
        GridView1.EditIndex = e.NewEditIndex;
        FillGridView();
    }
    /// <summary>
    /// Cancel the operation (e.g. edit)
    /// </summary>
    /// <param name="sender"></param>
    /// <param name="e"></param>
    protected void cancelRecord(object sender, GridViewCancelEditEventArgs e)
    {
        GridView1.EditIndex = -1;
        FillGridView();
    }
    /// <summary>
    /// Add new row into DataTable if no record found in Table
    /// </summary>
    /// <param name="sender"></param>
    /// <param name="e"></param>
    protected void AddNewRecord(object sender, EventArgs e)
    {
        try
        {
            if (GlobalClass.dt.Rows.Count > 0)
            {
                GridView1.EditIndex = -1;
                GridView1.ShowFooter = true;
                FillGridView();
            }
            else
            {
                GridView1.ShowFooter = true;
                DataRow dr = GlobalClass.dt.NewRow();
                dr["name"] = "0";
                dr["age"] = 0;
                dr["salary"] = 0;
                dr["country"] = "0";
                dr["city"] = "0";
                dr["photopath"] = "0";
                GlobalClass.dt.Rows.Add(dr);
                GridView1.DataSource = GlobalClass.dt;
                GridView1.DataBind();
                GridView1.Rows[0].Visible = false;
            }
        }
        catch
        {
            Response.Write("<script> alert('Row not added in DataTable...') </script>");
        }
    }
    /// <summary>
    /// Cancel new added record
    /// </summary>
    /// <param name="sender"></param>
    /// <param name="e"></param>
    protected void AddNewCancel(object sender, EventArgs e)
    {
        GridView1.ShowFooter = false;
        FillGridView();
    }
    /// <summary>
    /// Insert New Record
    /// </summary>
    /// <param name="sender"></param>
    /// <param name="e"></param>
    protected void InsertNewRecord(object sender, EventArgs e)
    {
        try
        {
            string strName = GlobalClass.dt.Rows[0]["name"].ToString();
            if (strName == "0")
            {
                GlobalClass.dt.Rows[0].Delete();
                GlobalClass.adap.Update(GlobalClass.dt);
            }
            TextBox txtName = GridView1.FooterRow.FindControl("txtNewName") as TextBox;
            TextBox txtAge = GridView1.FooterRow.FindControl("txtNewAge") as TextBox;
            TextBox txtSalary = GridView1.FooterRow.FindControl("txtNewSalary") as TextBox;
            TextBox txtCountry = GridView1.FooterRow.FindControl("txtNewCountry") as TextBox;
            TextBox txtCity = GridView1.FooterRow.FindControl("txtNewCity") as TextBox;
            FileUpload fuPhoto = GridView1.FooterRow.FindControl("fuNewPhoto") as FileUpload;
            Guid FileName = Guid.NewGuid();
            fuPhoto.SaveAs(Server.MapPath("~/Images/" + FileName + ".png"));
            DataRow dr = GlobalClass.dt.NewRow();
            dr["name"] = txtName.Text.Trim();
            dr["age"] = txtAge.Text.Trim();
            dr["salary"] = txtSalary.Text.Trim();
            dr["country"] = txtCountry.Text.Trim();
            dr["city"] = txtCity.Text.Trim();
            dr["photopath"] = "~/Images/" + FileName + ".png";
            GlobalClass.dt.Rows.Add(dr);
            GlobalClass.adap.Update(GlobalClass.dt);
            GridView1.ShowFooter = false;
            FillGridView();
        }
        catch
        {
            Response.Write("<script> alert('Record not added...') </script>");
        }
    }
    /// <summary>
    /// Update the record
    /// </summary>
    /// <param name="sender"></param>
    /// <param name="e"></param>
    protected void updateRecord(object sender, GridViewUpdateEventArgs e)
    {
        try
        {
            TextBox txtName = GridView1.Rows[e.RowIndex].FindControl("txtName") as TextBox;
            TextBox txtAge = GridView1.Rows[e.RowIndex].FindControl("txtAge") as TextBox;
            TextBox txtSalary = GridView1.Rows[e.RowIndex].FindControl("txtSalary") as TextBox;
            TextBox txtCountry = GridView1.Rows[e.RowIndex].FindControl("txtCountry") as TextBox;
            TextBox txtCity = GridView1.Rows[e.RowIndex].FindControl("txtCity") as TextBox;
            FileUpload fuPhoto = GridView1.Rows[e.RowIndex].FindControl("fuPhoto") as FileUpload;
            Guid FileName = Guid.NewGuid();
            if (fuPhoto.FileName != "")
            {
                fuPhoto.SaveAs(Server.MapPath("~/Images/" + FileName + ".png"));
                GlobalClass.dt.Rows[GridView1.Rows[e.RowIndex].RowIndex]["photopath"] = "~/Images/" + FileName + ".png";
                File.Delete(Server.MapPath(GlobalClass.imgEditPath));
            }
            GlobalClass.dt.Rows[GridView1.Rows[e.RowIndex].RowIndex]["name"] = txtName.Text.Trim();
            GlobalClass.dt.Rows[GridView1.Rows[e.RowIndex].RowIndex]["age"] = Convert.ToInt32(txtAge.Text.Trim());
            GlobalClass.dt.Rows[GridView1.Rows[e.RowIndex].RowIndex]["salary"] = Convert.ToInt32(txtSalary.Text.Trim());
            GlobalClass.dt.Rows[GridView1.Rows[e.RowIndex].RowIndex]["country"] = txtCountry.Text.Trim();
            GlobalClass.dt.Rows[GridView1.Rows[e.RowIndex].RowIndex]["city"] = txtCity.Text.Trim();
            GlobalClass.adap.Update(GlobalClass.dt);   
            GridView1.EditIndex = -1;
            FillGridView();
        }
        catch
        {
            Response.Write("<script> alert('Record updation fail...') </script>");
        }
    }
    /// <summary>
    /// Delete Record
    /// </summary>
    /// <param name="sender"></param>
    /// <param name="e"></param>
    protected void RowDeleting(object sender, GridViewDeleteEventArgs e)
    {
        try
        {
            GlobalClass.dt.Rows[GridView1.Rows[e.RowIndex].RowIndex].Delete();
            GlobalClass.adap.Update(GlobalClass.dt);
            // Get the image path for removing deleted's record image from server folder
            Image imgPhoto = GridView1.Rows[e.RowIndex].FindControl("imgPhoto") as Image;
            File.Delete(Server.MapPath(imgPhoto.ImageUrl));
            FillGridView();
        }
        catch
        {
            Response.Write("<script> alert('Record not deleted...') </script>");
        }
    }
}
Step 7:- Now, save and build you application and execute. Your application output display as following.
Insert, Delete, Update in GridView in ASP.Net using C#
It’s your application first screen. Because there is not data in table so it displace message “No record available”.
Step 8:- For inserting data, click on button “Add New Record”. Now fill the data. Every controls have validation for prohibited wrong input.  
Insert, Delete, Update in GridView in ASP.Net using C#
After filling data, your GridView looking as following.  Here I have inserted three records.
Insert, Delete, Update in GridView in ASP.Net using C#
Note: - Id are generated automatic for every new record.
Step 9:- For updating records click button “Edit” and change TextBox Data and you can select new photo of employee. For example in place of age “28”, updated with “30” and in place of salary “50000”, updated with “55000”, then click button “Update”. Through button “Cancel” you return previous stage.
Insert, Delete, Update in GridView in ASP.Net using C#
Step 10:- For record deletion, click on button “Delete”. Before deleting record, confirmation alert message are popup. Here I have deleted 3rd record (e.g. Andrew Deniel). After deleting record your GridView looks as following.
Insert, Delete, Update in GridView in ASP.Net using C#