Faraz Shah Khan

How to create event for a user control

2009-10-16T20:27:00Z

My article that will explain how to create event for a user control can be found here http://tinyurl.com/yhwd9xw

Error: Inconsistent accessibility: return type

2009-06-16T06:10:00Z

In one of my projects I found this error Inconsistent accessibility: return type...................... is less accessible than method ......... It was a quite strange error for me as I have not seen the same in past. My classes were defined as:

class MyClass1
{}

class MyClass2
{}

class MyClass3
{}

Solution to this problem is very easy, all I did is add public with all my classes.

public class MyClass1
{}

public class MyClass2
{}

public class MyClass3
{}

And once again, the day is saved by "Powerpuf Girls", I mean by adding public :).

Schema compatiblity error in configuring SqlMembershipProvider

2009-06-09T14:18:00Z

I was working with one of my projects in which I had to use Membership/Role providers. I run the wizard using aspnet_regsql.exe to create the structure of SqlMembershipProvider. I added few roles and users using ASP.Net Configuration. Everything worked fine tested my application multiple times and it worked very well. Then I generated the script from my local database for SqlMembershipProvider since we can not run the utility aspnet_regsql.exe on our test server. Everything went well so far. All the tables, views, stored procedures, roles were created and permissions were granted. Then when I try to run my application from the test server it gave me following error.

"The 'System.Web.Security.SqlMembershipProvider' requires a database schema compatible with schema version '1'. However, the current database schema is not compatible with this version. You may need to either install a compatible schema with aspnet_regsql.exe (available in the framework installation directory), or upgrade the provider to a newer version."

This was a bit confusing error for me since I had worked with SqlMembershipProvider in the past. Then I start recalling the difference between my previous and current deployment and the difference was in ealier deployments either I used aspnet_regsql.exe or copied the structure with data but this time I created the script and generate the structure.

Still no sign for me to detect the cause of error. Then I started checking the tables and I found that when we run aspnet_regsql.exe it not only creates the structure but insert some values as well in "aspnet_SchemaVersions" table which were missing in my test server. So created manual insert script to add following values.

-- --Table: [dbo].[aspnet_SchemaVersions]
-- --Insert
INSERT INTO [dbo].[aspnet_SchemaVersions] ([Feature], [CompatibleSchemaVersion], [IsCurrentVersion]) VALUES(N'common', N'1', 1)
INSERT INTO [dbo].[aspnet_SchemaVersions] ([Feature], [CompatibleSchemaVersion], [IsCurrentVersion]) VALUES(N'health monitoring', N'1', 1)
INSERT INTO [dbo].[aspnet_SchemaVersions] ([Feature], [CompatibleSchemaVersion], [IsCurrentVersion]) VALUES(N'membership', N'1', 1)
INSERT INTO [dbo].[aspnet_SchemaVersions] ([Feature], [CompatibleSchemaVersion], [IsCurrentVersion]) VALUES(N'personalization', N'1', 1)
INSERT INTO [dbo].[aspnet_SchemaVersions] ([Feature], [CompatibleSchemaVersion], [IsCurrentVersion]) VALUES(N'profile', N'1', 1)
INSERT INTO [dbo].[aspnet_SchemaVersions] ([Feature], [CompatibleSchemaVersion], [IsCurrentVersion]) VALUES(N'role manager', N'1', 1)

BINGO!!! After inserting these values my test server started working as good as my local machine :).

Authentication using web.config Credentials

2009-04-22T06:37:00Z

In one of my projects I have been asked to implement temporary security on sepcific module for internal usage and it was also suggested that I will not be putting more efforts on the same. First thing came in my mind was Membership/RoleProvider, but as I advised my planned solution they surprised me with the decision that I will not be using these providers and I should be using something more simpler and I was like Duh!!!

Any way I started thinking about a much more simpler solution as I have been alotted the biggest time period ever of 10-15 minutes max for this task :).

OK now I guess I should come to the point. During this process I realised that web.config credentials can be a good option as I personally don't wanted to implement any hardcoded authentication. It is very straight forward and simple but I had some problems implementing that solution so I thought to blog about how to authenticate using credentials incase if any one require the same.

All you need to do is to add some credentials in your web.config like this:

In the code block it can be authenticated like this:

if (FormsAuthentication.Authenticate(this.txtUserName.Text, this.txtPassword.Text))
{
  FormsAuthentication.SetAuthCookie(this.txtUserName.Text, false);
  FormsAuthentication.RedirectFromLoginPage(this.txtUserName.Text, false);
}
else
{
  Response.Write("Invalid login details. Please try again.");
}

I hope it will be helpful for others as well. And yes it can be done in 15 minutes :)

Another browser in the row (Google Chrome)

2008-09-02T16:33:00Z

Today I just found that my friend Google launched its web browser named Chrome which is suppose to be availble for download on 2nd Sep 2008 from this link Google Chrome, but unfortunately for some unknown good reason I am unable to download this guy, as whenever I click the link it takes me to Google home page. However I felt a little better when I successfully opened the ebook of Chrome after tearing off my hair because of the download link.

Now I am sure that almost everyone try to download this browser in curiosity as what Google launched after such a long time. Well why I kept the title of this blog as Another browser in the row because being a Software Engineer I will have to test my applications with one more browser. I hope we will not be having javascript and layout issues in this one and everything will work smoothly.

By the way you should check out the ebook link of Chrome as they talked about this new guy in a comic way and it looks quite catchy in this way.

Ahann!!! finally while writting this blog I found this blog link http://uzeeinc.wordpress.com/2008/09/02/download-google-chrome-browser/ and now I came to know that unknown good reason why I couldn't download this guy.

Regex to find URL within text and make them as link

2008-08-09T09:53:00Z

Some time back on the form somebody was looking for some help in searching URL within text and make those URLs as link. Me and that guy tried various regex but the one that worked out I thought to put it on the blog so that it can help me and others later. Regex itself is:

-------- In VB.Net ---------
Dim regx As New Regex("http://([\w+?\.\w+])+([a-zA-Z0-9\~\!\@\#\$\%\^\&\*_\-\=\+\\\/\?\.\:\;\'\,]*)?", RegexOptions.IgnoreCase)

-------- In C#.Net ---------
Regex regx = new Regex("http://([\\w+?\\.\\w+])+([a-zA-Z0-9\\~\\!\\@\\#\\$\\%\\^\\&\\*\$\$_\\-\\=\\+\\\\\\/\\?\\.\\:\\;\\'\\,]*)?", RegexOptions.IgnoreCase);

And I used following method to convert the URLs into link within text.

-------- In VB.Net ---------
Protected Function MakeLink(ByVal txt As String) As String
Dim regx As New Regex("http://([\w+?\.\w+])+([a-zA-Z0-9\~\!\@\#\$\%\^\&\*_\-\=\+\\\/\?\.\:\;\'\,]*)?", RegexOptions.IgnoreCase)

Dim mactches As MatchCollection = regx.Matches(txt)

        For Each match As Match In mactches
            txt = txt.Replace(match.Value, "<a href='" & match.Value & "'>" & match.Value & "</a>")
        Next

Return txt
End Function

------- In C#.Net --------
protected string MakeLink(string txt)
{
    Regex regx = new Regex("http://([\\w+?\\.\\w+])+([a-zA-Z0-9\\~\\!\\@\\#\\$\\%\\^\\&\\*\$\$_\\-\\=\\+\\\\\\/\\?\\.\\:\\;\\'\\,]*)?", RegexOptions.IgnoreCase);

    MatchCollection mactches = regx.Matches(txt);

    foreach (Match match in mactches) {
        txt = txt.Replace(match.Value, "<a href='" + match.Value + "'>" + match.Value + "</a>");
    }

    return txt;
}

File Upload control AJAX effect

2008-08-03T06:42:00Z

Since long I was wondering on how I will be able to use FileUpload control inside UpdatePanel and I am sure there will be lot of other people who were expecting the same to be working. I found an intersting video article by Joe Stagner in which he described how to use the FileUpload control inside iframe to give some AJAX effect. You can find this video here. http://www.asp.net/learn/videos/video-254.aspx

Mutually exclusive checkbox in GridView using Javascript

2008-08-02T11:00:00Z

I response to one of my blog post entry I received few queries regarding mutually exclusive checkbox within GirdView, meaning if there are two checkboxes in a row only one can be selected at a time. If checkbox1 is selected and you select checkbox2 then checkbox1 should be deselected. Following javascript and html can be used.

Code Behind:

----------------------------------.vb file if VB.Net is the language ------------------------------------

Protected Sub GridView1_RowDataBound(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.GridViewRowEventArgs) Handles GridView1.RowDataBound
        If (e.Row.RowType = DataControlRowType.DataRow) Then
            DirectCast(e.Row.FindControl("cbStatus1"), CheckBox).Attributes.Add("onclick", "javascript:checkMutuallyExclusive('" & DirectCast(e.Row.FindControl("cbStatus2"), CheckBox).ClientID & "')")
            DirectCast(e.Row.FindControl("cbStatus2"), CheckBox).Attributes.Add("onclick", "javascript:checkMutuallyExclusive('" & DirectCast(e.Row.FindControl("cbStatus1"), CheckBox).ClientID & "')")
        End If
End Sub

----------------------------------.cs file if C#.Net is the language ------------------------------------

protected void GridView1_RowDataBound(object sender, System.Web.UI.WebControls.GridViewRowEventArgs e)
{
    if ((e.Row.RowType == DataControlRowType.DataRow)) {
        ((CheckBox)e.Row.FindControl("cbStatus1")).Attributes.Add("onclick", "javascript:checkMutuallyExclusive('" + ((CheckBox)e.Row.FindControl("cbStatus2")).ClientID + "')");
        ((CheckBox)e.Row.FindControl("cbStatus2")).Attributes.Add("onclick", "javascript:checkMutuallyExclusive('" + ((CheckBox)e.Row.FindControl("cbStatus1")).ClientID + "')");
    }
}

Login through cookies

2008-03-23T08:21:00Z

Different forums are filled with the questions regarding how to manually implement cookies for login or in other words how to implement "Remeber me" option.

Following is the code that will give the idea of how to achieve this task.

Controls used
1. TextBox, ID = TbUserName
2. TextBox, ID = TbPassword
3. CheckBox, ID = CbRememberMe
4. Button, ID = BtLogin
5. LinkButton, ID = lbSignout

------------------If you are using VB.Net-------------------------

Partial Class _Default
Inherits System.Web.UI.Page

    Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
        If Not IsPostBack Then
            'Check if the browser support cookies
            If Request.Browser.Cookies Then
               'Check if the cookies with name PBLOGIN exist on user's machine
                If Request.Cookies("PBLOGIN") IsNot Nothing Then
                    'Pass the user name and password to the VerifyLogin method
                    Me.VerifyLogin(Request.Cookies("PBLOGIN")("UNAME").ToString(), Request.Cookies("PBLOGIN")("UPASS").ToString())
                End If
            End If
        End If
    End Sub

    Protected Sub BtLogin_Click(ByVal sender As Object, ByVal e As System.EventArgs)
        'check if remember me checkbox is checked on login
        If (Me.CbRememberMe.Checked) Then
            'Check if the browser support cookies
            If (Request.Browser.Cookies) Then
                'Check if the cookie with name PBLOGIN exist on user's machine
                If (Request.Cookies("PBLOGIN") Is Nothing) Then
                    'Create a cookie with expiry of 30 days
                    Response.Cookies("PBLOGIN").Expires = DateTime.Now.AddDays(30)
                    'Write username to the cookie
                    Response.Cookies("PBLOGIN").Item("UNAME") = Me.TbUserName.Text
                    'Write password to the cookie
                    Response.Cookies("PBLOGIN").Item("UPASS") = Me.TbPassword.Text
  'If the cookie already exist then wirte the user name and password on the cookie
                Else
                    Response.Cookies("PBLOGIN").Item("UNAME") = Me.TbUserName.Text
                    Response.Cookies("PBLOGIN").Item("UPASS") = Me.TbPassword.Text
                End If
            End If
        End If

Me.VerifyLogin(Me.TbUserName.Text, Me.TbPassword.Text)
End Sub

    Protected Sub VerifyLogin(ByVal UserName As String, ByVal Password As String)
        Try
            'If login credentials are correct
                 'Redirect to the user page
            'else
                 'prompt user for invalid password
            'end if
        Catch ex as System.Exception
            Response.Write(ex.Message)
        End Try
    End Sub

    Protected Sub lbSignout_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles lbSignout.Click
'Check iIf the cookies with name PBLOGIN exist on user's machine
        If (Request.Cookies("PBLOGIN") IsNot Nothing) Then
            'Expire the cookie
            Response.Cookies("PBLOGIN").Expires = DateTime.Now.AddDays(-30)
        End If

'Redirect to the login page
End Sub
End Class

------------------If you are using C#.Net-------------------------

partial class _Default : System.Web.UI.Page
{

    protected void Page_Load(object sender, System.EventArgs e)
    {
        if (!IsPostBack)
        {
            //Check if the browser support cookies
            if (Request.Browser.Cookies)
            {
                //Check if the cookies with name PBLOGIN exist on user's machine
                if (Request.Cookies("PBLOGIN") != null)
                {
                    //Pass the user name and password to the VerifyLogin method
                    this.VerifyLogin(Request.Cookies("PBLOGIN")("UNAME").ToString(), Request.Cookies("PBLOGIN")("UPASS").ToString());
                }
            }
        }
    }

    protected void BtLogin_Click(object sender, System.EventArgs e)
    {
        //check if remember me checkbox is checked on login
        if ((this.CbRememberMe.Checked))
        {
            //Check if the browser support cookies
            if ((Request.Browser.Cookies))
            {
                //Check if the cookie with name PBLOGIN exist on user's machine
                if ((Request.Cookies("PBLOGIN") == null))
                {
                    //Create a cookie with expiry of 30 days
                    Response.Cookies("PBLOGIN").Expires = DateTime.Now.AddDays(30);
                    //Write username to the cookie
                    Response.Cookies("PBLOGIN").Item("UNAME") = this.TbUserName.Text;
                    //Write password to the cookie
                    Response.Cookies("PBLOGIN").Item("UPASS") = this.TbPassword.Text;
                }
                //If the cookie already exist then wirte the user name and password on the cookie
                else
                {
                    Response.Cookies("PBLOGIN").Item("UNAME") = this.TbUserName.Text;
                    Response.Cookies("PBLOGIN").Item("UPASS") = this.TbPassword.Text;
                }
            }
        }

        this.VerifyLogin(this.TbUserName.Text, this.TbPassword.Text);
    }

    protected void VerifyLogin(string UserName, string Password)
    {
        try
        {
             //If login credentials are correct
                  //Redirect to the user page
             //else
                  //prompt user for invalid password
             //end if
        }
        catch (System.Exception ex)
        {
            Response.Write(ex.Message);
        }
    }

    protected void lbSignout_Click(object sender, System.EventArgs e)
    {
        //Check iIf the cookies with name PBLOGIN exist on user's machine
        if ((Request.Cookies("PBLOGIN") != null))
        {
            //Expire the cookie
            Response.Cookies("PBLOGIN").Expires = DateTime.Now.AddDays(-30);
        }

        //Redirect to the login page
    }

}

Javascript to add bookmark option on your website

2008-03-13T07:05:00Z

If you want to add an option that users can click a button on your website and it will open up bookmark option. Following is the code that will perform this task.

<html>
<body>
<SCRIPT LANGUAGE="JavaScript">
function bookmark(url, description)
{
if (navigator.appName=='Microsoft Internet Explorer')
{
window.external.AddFavorite(url, description);
}
else
{
alert('This option works with IE only as of now.');
}
}

</SCRIPT>
<input type="Button" ID="btnBookMark" onClick="bookmark('http://mypage.aspx','MyWebsite')" value="Bookmark" />
</body>
</html>

Javascript Enable/Disable Dropdown in Gridview using Checkboxes

2008-02-27T06:59:00Z

If you come up with some requirement in which you have a Checkbox and a DropDownList in GridView control and you are requried to enable disable the DropDownList on the basis of the CheckBox value you can use following Code.

-----------------------------------.aspx file ----------------------------------

----------------------------------.vb file if VB.Net is the language ------------------------------------

----------------------------------.cs file if C#.Net is the language ------------------------------------

Reading file content from different webserver using HttpWebRequest

2008-02-16T12:03:00Z

I was replying to one of the post on the ASP.Net forum in which the requirement was like reading txt file contents from different webservers. When he got satisfied with the solution then I thought to put the piece of code in my blog as well for others and my future reference.

--- .vb file if VB.Net is the language ---

        If Not (IsPostBack) Then
            Try
                Dim fr As System.Net.HttpWebRequest = DirectCast(System.Net.HttpWebRequest.Create(New Uri("http://weblogs.asp.net/farazshahkhan")), System.Net.HttpWebRequest)
                'In above code http://weblogs.asp.net/farazshahkhan is used as an example it can be different domain with different filename and extension
                If (fr.GetResponse().ContentLength > 0) Then
                    Dim str As New System.IO.StreamReader(fr.GetResponse().GetResponseStream())
                    Response.Write(str.ReadToEnd())
                End If

            Catch ex As System.Net.WebException
                Response.Write("File does not exist.")
            End Try

        End If

--- .cs file if C#.Net is the language ---

if (!(IsPostBack))
    {
        try {
            System.Net.HttpWebRequest fr = (System.Net.HttpWebRequest)System.Net.HttpWebRequest.Create(new Uri("http://weblogs.asp.net/farazshahkhan"));
            //In above code http://weblogs.asp.net/farazshahkhan is used as an example it can be different domain with different filename and extension
            if ((fr.GetResponse().ContentLength > 0)) {
                System.IO.StreamReader str = new System.IO.StreamReader(fr.GetResponse().GetResponseStream());
                Response.Write(str.ReadToEnd());
            }
        }

        catch (System.Net.WebException ex) {
            Response.Write("File does not exist.");
        }

    }

Passing value from popup window to parent form's TextBox

2008-02-16T09:14:00Z

Once again seen lot of questions on the forum related to passing values from popup window to the parent form textbox. Specially when they have some GridView type control in the popup. In the following example I will be using two forms, parent form will be parent.aspx and popup will be popup.aspx. Also note that my parent.aspx form is derived from some MasterPage. Code is provided both in VB.Net and C#.Net.

--- .aspx of parent form ---

--- .vb of parent.aspx if vb.net is the language ---

If Not IsPostBack Then
Me.Button1.Attributes.Add("onclick", "javascript:return OpenPopup()")
End If

--- .cs of parent.aspx if C#.net is the language ---

if !(IsPostBack)
{
this.Button1.Attributes.Add("onclick", "javascript:return OpenPopup()");
}

--- .aspx of popup form ---

--- .vb file if vb.net is the language ---

Protected Sub GridView1_RowDataBound(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.GridViewRowEventArgs) Handles GridView1.RowDataBound
        If (e.Row.RowType = DataControlRowType.DataRow) Then
            DirectCast(e.Row.FindControl("btnSelect"), Button).Attributes.Add("onclick", "javascript:GetRowValue('" & e.Row.Cells(1).Text & "')") 'assuming that the required value column is the second column in gridview
        End If
    End Sub

--- .cs file if C#.net is the language ---

protected void GridView1_RowDataBound(object sender, System.Web.UI.WebControls.GridViewRowEventArgs e)
{
    if ((e.Row.RowType == DataControlRowType.DataRow)) {
        ((Button)e.Row.FindControl("btnSelect")).Attributes.Add("onclick", "javascript:GetRowValue('" + e.Row.Cells(1).Text + "')");
        //assuming that the required value column is the second column in gridview
    }
}

I hope the code above is straight forward and easy to understand.

Happy Coding!!!

Javascript to display time on Web page

2008-02-13T11:11:00Z

Javascript to display continuous time on the Web page. By continuous it means that it will be displayed second by second.

<asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>

If you are using normal Webform then it can be called on Body load event. If you are using MasterPage then it can be called within ContentTemplate at the end afte all the controls will be rendered.

Check/Uncheck checkboxes in GridView using javascript

2008-02-13T09:58:00Z

Seen a lot of questions regarding how to check/uncheck CheckBoxes within a GridView control using JavaScript. So I thought to put it on my blog for quick reference for others and for myself. Following is the code:
------------------------------------------- .aspx code ---------------------------------------------
<script type="text/javascript">
function SelectAll(id)
      {
      var frm = document.forms[0];

            for (i=0;i<frm.elements.length;i++)
            {
                if (frm.elements[i].type == "checkbox")
                {
          frm.elements[i].checked = document.getElementById(id).checked;
                }
            }
        }

</script>
<asp:GridView ID="GridView1" runat="server" DataSourceID="SqlDataSource1" Width="400px">
        <Columns>
            <asp:TemplateField>
                <AlternatingItemTemplate>
                    <asp:CheckBox ID="CheckBox1" runat="server" />
                </AlternatingItemTemplate>
                <ItemTemplate>
                    <asp:CheckBox ID="CheckBox1" runat="server" />
                </ItemTemplate>
                <HeaderTemplate>
                    <asp:CheckBox ID="cbSelectAll" runat="server" Text="Select All" />
                </HeaderTemplate>
                <HeaderStyle HorizontalAlign="Left" />
                <ItemStyle HorizontalAlign="Left" />
            </asp:TemplateField>
        </Columns>
    </asp:GridView>

----------------------------------------- .vb file if VB.Net is the language ------------------------------------------
VB.Net Code
Protected Sub GridView1_RowDataBound(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.GridViewRowEventArgs) Handles GridView1.RowDataBound
        If (e.Row.RowType = DataControlRowType.Header) Then
            'adding an attribut for onclick event on the check box in the hearder and passing the ClientID of the Select All checkbox
            DirectCast(e.Row.FindControl("cbSelectAll"), CheckBox).Attributes.Add("onclick", "javascript:SelectAll('" & DirectCast(e.Row.FindControl("cbSelectAll"), CheckBox).ClientID & "')")
        End If
    End Sub

----------------------------------------- .cs file if C#.Net is the language ------------------------------------------
C#.Net Code

protected void GridView1_RowDataBound(object sender, System.Web.UI.WebControls.GridViewRowEventArgs e)
    {
        if ((e.Row.RowType == DataControlRowType.Header))
        {
            //adding an attribut for onclick event on the check box in the hearder and passing the ClientID of the Select All checkbox
            ((CheckBox)e.Row.FindControl("cbSelectAll")).Attributes.Add("onclick", "javascript:SelectAll('" + ((CheckBox)e.Row.FindControl("cbSelectAll")).ClientID + "')");
        }
    }