Free ASP.NET Source Code & Tutorial

Tuesday, November 8, 2011

How to get the random string in asp.net

Here is the code in code-behind file.

private static string RandomString(int size, bool lowerCase) {

StringBuilder builder = new StringBuilder();

Random random = new Random();

char ch;

for(int i = 0;i < size;i++) {

ch = Convert.ToChar(Convert.ToInt32(26 * random.NextDouble() + 65));

builder.Append(ch);

}

if(lowerCase)

return builder.ToString().ToLower();

return builder.ToString();

}

You can pass the parameters such as length of string and lower case or not.

Sunday, November 6, 2011

How to validate the birth date with javascript - Integer, Length and next focus.

Sometime, we are vulnerable to check the user input and client side validation is better than server side in that circumstances. This example show you how to check the user input for Birth Date.

Validating Birth Date with Javascript

Here is the javascript to put into <head> tag.

<script type="text/javascript">
    function OnKeyUpCheck(obj, n, e) {
        var unicode = e.keyCode ? e.keyCode : e.charCode
        var ch;
        var str = obj.value;
        if (str.length == 0) return true;
        for (var i = 0; i < str.length; i++) {
            ch = str.substring(i, i + 1);
            if ((ch < "0") || (ch > "9")) {
                alert("INVALID CHARECTER 0-9");
                obj.value = '';
            }
        }
        if (obj.value.length == obj.maxLength) {
            if ((unicode > 47) && (unicode < 128)) {
                n.focus();
            }
        }
    }
</script>

Add the below snippet to <form> tag.

<form id="form1" runat="server">
    <asp:Label ID="Label4" runat="server" >Birthdate(DD/MM/YYYY)</asp:Label>
     <asp:TextBox ID="txtDD" runat="server" MaxLength="2" Width="41px"
        AutoCompleteType="Disabled"></asp:TextBox>
    <asp:RequiredFieldValidator ID="RequiredFieldValidator2" runat="server" ControlToValidate="txtDD"
        Display="Dynamic" ErrorMessage="*" ValidationGroup="Empty"
        ForeColor="Red"></asp:RequiredFieldValidator>
    <asp:TextBox ID="txtMM" runat="server" MaxLength="2" Width="41px"
        AutoCompleteType="Disabled"></asp:TextBox>
    <asp:RequiredFieldValidator ID="RequiredFieldValidator1" runat="server" ControlToValidate="txtMM"
        Display="Dynamic" ErrorMessage="*" ValidationGroup="Empty"
        ForeColor="Red"></asp:RequiredFieldValidator>
    <asp:TextBox ID="txtYY" runat="server" MaxLength="4" Width="56px"
        AutoCompleteType="Disabled"></asp:TextBox>
    <asp:RequiredFieldValidator ID="RequiredFieldValidator3" runat="server" ControlToValidate="txtYY"
        Display="Dynamic" ErrorMessage="*" ValidationGroup="Empty"
        ForeColor="Red"></asp:RequiredFieldValidator>
     
    <asp:Button ID="btnSubmit" runat="server" Text="Submit" ValidationGroup="Empty" />
</form>

In codebehind, add the following code.

protected void Page_Load(object sender, EventArgs e)

{

      txtDD.Attributes.Add("OnKeyUp", "OnKeyUpCheck(txtDD, txtMM, event)");

      txtMM.Attributes.Add("OnKeyUp", "OnKeyUpCheck(txtMM, txtYY, event)");

      txtYY.Attributes.Add("OnKeyUp", "OnKeyUpCheck(txtYY, btnSubmit, event)");

}

When you type invalid char(except 0-9), it show javascript alert. its length is meet and then it move focus to next control. Now, in web form, it uses server validation controls for empty text and they have ValidationGroup property.

Saturday, November 5, 2011

How to check English character or not with javascript

The following is the javascript in head tag.

<script type="text/javascript">
function isValidEnglishLetter(object) {
param = object.value;
re = /[^A-Za-z0-9_\s\t\n\,\.\'\\?\!\@\#\$\%\^\&\*\{\}\[\]\<\>\/\+\-\^\?\~\|\:]/;
result = re.test(param);
if (!result) {
return true;
}
else {
alert("Only English characters and numerics are allowed.");
object.value = '';
object.select();
object.focus();
return false;
}
}
</script>

Here is in form.

<form id="form1" runat="server">
<asp:textbox id="txtNumber" runat="server" MaxLength="20" Width="100px" AutoCompleteType="Disabled"></asp:textbox>
<asp:Button ID="btnClick" runat="server" Text="Click"/>
</form>

In code behind,

protected void Page_Load(object sender, EventArgs e)
{
//For Keyup on textbox
txtNumber.Attributes.Add("OnKeyUp", "isValidEnglishLetter(this)");
//Otherwise, for button click
btnClick.Attributes.Add("OnClick", "isValidEnglishLetter(txtNumber)");
}

It will show the Alert message whenever you type other character(such as Japan character).

Friday, November 4, 2011

How to popup your page in the center of computer screen using Javascript.

Sometime, we want to show a small window in the center of computer screen and on top of the main browser window. This small window is popularly known as a popup. Let's start here for Javascript Popup.

Javascript Popup

First, create "JavaScriptPopup.aspx" and put the below script to <head> tag.

<script type="text/javascript">
    function showPopUp(url) {
        var w = screen.availWidth; 
        var h = screen.availHeight;
        var popW = 500;
        var popH = 300;
        var leftPos = (w - popW) / 2;
        var topPos = (h - popH) / 2;
        newwindow = window.open(url, 'Terms of Use', 'width=' + popW + ',height=' + popH + ',top=' + topPos +
        ',left=' + leftPos + ',toolbar=no,status=no,menubar=no,location=no,scrollbars=yes,resizable=no');
        if (window.focus) { newwindow.focus() } //place the focus on the new window
        return false; //to prevent the browser from following the actual
link.
   }
</script>

Add the following code to <form> tag.

<form id="form1" runat="server">
        <a href="tou.aspx" onclick="return showPopUp('tou.aspx')">Link to popup</a>

 </form> 

Second, create "tou.aspx" for content (Popup) as below.

<form id="form1" runat="server">
    <p>
        <strong>Basic Terms</strong>
        <br />
        You must be 13 years or older to use this site.
        <br />
        You are responsible for any activity that occurs under your blog name.
        <br />
        You are responsible for keeping your password secure.
        <br />
        You must not abuse, harass, threaten, impersonate or intimidate other iBlogSeeker
        users.
        <br />
        You may not use the iBlogSeeker.com service for any illegal or unauthorized purpose.
        International users agree to comply with all local laws regarding online conduct
        and acceptable content.
        <p><a href="javascript:self.close()">Close</a> the popup.</p>
    </p>

</form>

When you click the link, it show Popup page and "Close" link for disappear the Popup. Enjoy the script!

Javascript popup details

How to detect the client IP in asp.net

You just use the following code snippet. It is perfect also.

string clientIP = Request.ServerVariables["HTTP_X_FORWARDED_FOR"];

if (clientIP == "" || clientIP == null)

{

clientIP = Request.ServerVariables["REMOTE_ADDR"];

}

Enjoy the programming!
Thank

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