validation involving 2 controls

mehdi62b · December 16th, 2004, 06:11 PM

you dont need to put any tag,we have a string variable('s')that keeps JavaScript codes,

Code:

//JavaScript Syntax
var txtbox1=document.getElementById('TextBox1');//finds first textbox
var txtbox2=document.getElementById('TextBox2');//finds second textbox

I supposed the ID's of your textboxes were TextBox1 and TextBox2(in code-behind) then we test
value property(JavaScript property) of every textbox according to your condition,

Code:

//JavaScript Syntax
if (txtbox1.value=='' && txtbox2.value=='' || txtbox1.value!='' && txtbox2.value!='')
    {window.alert('Validation not acceptable.');return false;}

I return false because I dont want Button_Click event to be fired off,
now I should add this javascript code to onclick attribute somewhere like Page_Load,

Code:

//C# Syntax
//s keeps that javascript code I mentioned
Button.Attributes.Add("onclick",s);

There are two points here,
1-Button_Click is a server-side event for the Button,
2-onclick attribute is a client-side event for the same Button,
when an user clicks the Button first client-side event check the condition,
if condition is true(invalid inputs)the onclick attribute shows a po pup window,
and return false so Button_Click is not fired off any more,
but if condition is false(valid inputs),Button_Click is fired,
(put codes come after a successful validation in your Button_Click event)

Code:

//Final Code
private void Page_Load(object sender, System.EventArgs e)
{
    if(!Page.IsPostBack)
    {
           string s="";
           s+="var txtbox1=document.getElementById('TextBox1');var txtbox2=document.getElementById('TextBox2');";
           s+="if (txtbox1.value=='' && txtbox2.value=='' || txtbox1.value!='' && txtbox2.value!=''){window.alert('Validation not acceptable.');return false;}";
           Button.Attributes.Add("onclick",s);
    }
}
private void Button_Click(object sender, System.EventArgs e)
{
      //codes are executed on the server-side after a successful validation
}

this method works just like this page,look at the bottom of this page,
if you try to send an empty message a po pup window notices you,
and stops sending your request to server.
_____________________________
Mehdi.
software engineering student.
Looking for a good job for summer 2005.

Renu · December 20th, 2004, 05:31 PM

Mehdi-
this code works just Great! Thanks a lot. It is so simple and does the needful. Again, thanks for taking all the time to find the solution.
Renu

nashnash · December 21st, 2004, 06:28 AM

--save this as 'te.aspx'-----

<%@ Page language="c#" Codebehind="te.aspx.cs" AutoEventWireup="false" Inherits="Insight.te" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" >
<script language="javascript">
    function validate()
    {
        var strText1;
        var strText2;
        strText1=document.getElementById("TextBox1").value ;
        strText2=document.getElementById("TextBox2").value ;
        if(strText1=="" && strText2 =="")
        {
            alert("Please enter any textboxes");
            document.getElementById("lblMsg").innerHTML ="One of the textbox must be filled";
            return false;
        }
    }
</script>
<form id="Form1" runat="server">
    <table>
        <tr>
            <td>
                <div id="lblMsg"></div>
            </td>
        </tr>
        <tr>
            <td>
                <asp:textbox id="TextBox1" runat="server"
        Width="76px"></asp:textbox>
        <asp:textbox id="TextBox2" runat="server"
        Width="76px"></asp:textbox>
        <asp:button id="Button1" runat="server"
        Text="Button"></asp:button>
            </td>
        </tr>
    </table>

    </p>
    <p>

        </p>
        </form>
-----save this as 'te.aspx.cs'-------
using System;
using System.Collections;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Web;
using System.Web.SessionState;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;

namespace Insight
{
    /// <summary>
    /// Summary description for te.
    /// </summary>
    public class te : System.Web.UI.Page
    {
        protected System.Web.UI.WebControls.TextBox TextBox1;
        protected System.Web.UI.WebControls.TextBox TextBox2;
        protected System.Web.UI.WebControls.Button Button1;

        private void Page_Load(object sender, System.EventArgs e)
        {
            // Put user code to initialize the page here
            Button1.Attributes.Add("onclick","javascript:retur n validate();");
        }

        #region Web Form Designer generated code
        override protected void OnInit(EventArgs e)
        {
            //
            // CODEGEN: This call is required by the ASP.NET Web Form Designer.
            //
            InitializeComponent();
            base.OnInit(e);
        }

        /// <summary>
        /// Required method for Designer support - do not modify
        /// the contents of this method with the code editor.
        /// </summary>
        private void InitializeComponent()
        {
            this.Load += new System.EventHandler(this.Page_Load);

        }
        #endregion
    }
}

Thanks
Nash

nashnash · December 21st, 2004, 06:30 AM

please copy and pase and u will get the result.
--save this as 'te.aspx'-------------
<%@ Page language="c#" Codebehind="te.aspx.cs" AutoEventWireup="false" Inherits="Insight.te" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" >
<script language="javascript">
    function validate()
    {
        var strText1;
        var strText2;
        strText1=document.getElementById("TextBox1").value ;
        strText2=document.getElementById("TextBox2").value ;
        if(strText1=="" && strText2 =="")
        {
            alert("Please enter any textboxes");
            document.getElementById("lblMsg").innerHTML ="One of the textbox must be filled";
            return false;
        }
    }
</script>
<form id="Form1" runat="server">
    <table>
        <tr>
            <td>
                <div id="lblMsg"></div>
            </td>
        </tr>
        <tr>
            <td>
                <asp:textbox id="TextBox1" runat="server"
        Width="76px"></asp:textbox>
        <asp:textbox id="TextBox2" runat="server"
        Width="76px"></asp:textbox>
        <asp:button id="Button1" runat="server"
        Text="Button"></asp:button>
            </td>
        </tr>
    </table>

    </p>
    <p>

        </p>
        </form>

-------------save this as 'te .aspx.cs'------------
using System;
using System.Collections;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Web;
using System.Web.SessionState;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;

namespace Insight
{
    /// <summary>
    /// Summary description for te.
    /// </summary>
    public class te : System.Web.UI.Page
    {
        protected System.Web.UI.WebControls.TextBox TextBox1;
        protected System.Web.UI.WebControls.TextBox TextBox2;
        protected System.Web.UI.WebControls.Button Button1;

        private void Page_Load(object sender, System.EventArgs e)
        {
            // Put user code to initialize the page here
            Button1.Attributes.Add("onclick","javascript:retur n validate();");
        }

        #region Web Form Designer generated code
        override protected void OnInit(EventArgs e)
        {
            //
            // CODEGEN: This call is required by the ASP.NET Web Form Designer.
            //
            InitializeComponent();
            base.OnInit(e);
        }

        /// <summary>
        /// Required method for Designer support - do not modify
        /// the contents of this method with the code editor.
        /// </summary>
        private void InitializeComponent()
        {
            this.Load += new System.EventHandler(this.Page_Load);

        }
        #endregion
    }
}

nashnash · December 21st, 2004, 06:33 AM

----save this as 'te.aspx'--------
<%@ Page language="c#" Codebehind="te.aspx.cs" AutoEventWireup="false" Inherits="Insight.te" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" >
<script language="javascript">
    function validate()
    {
        var strText1;
        var strText2;
        strText1=document.getElementById("TextBox1").value ;
        strText2=document.getElementById("TextBox2").value ;
        if(strText1=="" && strText2 =="")
        {
            alert("Please enter any textboxes");
            document.getElementById("lblMsg").innerHTML ="One of the textbox must be filled";
            return false;
        }
    }
</script>
<form id="Form1" runat="server">
    <table>
        <tr>
            <td>
                <div id="lblMsg"></div>
            </td>
        </tr>
        <tr>
            <td>
                <asp:textbox id="TextBox1" runat="server"
        Width="76px"></asp:textbox>
        <asp:textbox id="TextBox2" runat="server"
        Width="76px"></asp:textbox>
        <asp:button id="Button1" runat="server"
        Text="Button"></asp:button>
            </td>
        </tr>
    </table>

    </p>
    <p>

        </p>
        </form>

----save this as 'te.aspx.cs' ------

using System;
using System.Collections;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Web;
using System.Web.SessionState;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;

namespace Insight
{
    /// <summary>
    /// Summary description for te.
    /// </summary>
    public class te : System.Web.UI.Page
    {
        protected System.Web.UI.WebControls.TextBox TextBox1;
        protected System.Web.UI.WebControls.TextBox TextBox2;
        protected System.Web.UI.WebControls.Button Button1;

        private void Page_Load(object sender, System.EventArgs e)
        {
            // Put user code to initialize the page here
            Button1.Attributes.Add("onclick","javascript:retur n validate();");
        }

        #region Web Form Designer generated code
        override protected void OnInit(EventArgs e)
        {
            //
            // CODEGEN: This call is required by the ASP.NET Web Form Designer.
            //
            InitializeComponent();
            base.OnInit(e);
        }

        /// <summary>
        /// Required method for Designer support - do not modify
        /// the contents of this method with the code editor.
        /// </summary>
        private void InitializeComponent()
        {
            this.Load += new System.EventHandler(this.Page_Load);

        }
        #endregion
    }
}