Want to protect your cyber security and still get fast solutions? Ask a secure question today.Go Premium

x
  • Status: Solved
  • Priority: Medium
  • Security: Public
  • Views: 470
  • Last Modified:

Preventing databind when page is invalid

I have a page set up as follows:

A TextBox that accepts a value, which will be used as a parameter in the ObjectDataSource
A CustomValidator on that textbox (it checks to make sure the string represents a date)
A GridView, with an associated ObjectDataSource, having a SelectParameter set to the TextBox.

My problem is that the GridView rebinds on every postback, causing a problem if the textbox is invalid, the database will throw an exception.  Ideally, I would like the page to simply display the form again, with the old GridView data, and an error message from the Validators.  I thought this would be built in, because why would anybody want to use an invalid control as the source of a parameter.

If I'm confusing you, I can post snippets of my code to help clarify.
0
marker126
Asked:
marker126
  • 4
1 Solution
 
kGeniusCommented:
First you can read this post on 4guysfromrolla: http://aspnet.4guysfromrolla.com/demos/IsPrime.Client.aspx

You should check "if (Page.IsValid) { }" before you do you're databind...

Hope this help,
you can always post the code if you want more help.

kGenius
0
 
marker126Author Commented:
Maybe I should clarify my situation:

I'm using ASP.NET 2.0, and the GridView is set at design-time to use the ObjectDataSource.  I have written no code to actually control the binding of the GridView, it has all been done for me (which is one of my biggest complaints about 2.0, a great deal of the details have been hidden)

<asp:TextBox ID="txtBeginDate" runat="server" CausesValidation="True"></asp:TextBox>

<asp:CustomValidator ID="valBeginDate" runat="server"
   ControlToValidate="txtBeginDate"></asp:CustomValidator>

<asp:GridView ID="gvData" runat="server" AutoGenerateColumns="True"></asp:GridView>

<asp:ObjectDataSource ID="dsData" runat="server"
      OldValuesParameterFormatString="original_{0}"
      SelectMethod="GetData"
      TypeName="dsOrders.OrdersTableAdapter">
   <SelectParameters>
      <asp:ControlParameter ControlID="txtBeginDate" Name="BeginDate" PropertyName="Text"
            Type="DateTime" />
   </SelectParameters>
</asp:ObjectDataSource>

So when txtBeginDate/valBeginDate is invalid, I want to prevent the GridView/ObjectDataSource from using the textbox to bind data.
0
 
kGeniusCommented:
You could write a javascript with a function called ValidateDate(sender, args) { }

This function must return args.IsValid=false; when the date is not valid.

ie
<SCRIPT LANGUAGE="javascript" >
function ValidateDate(sender, args) {

  bValidDate= //check date here returns boolean;

  if (bValidDate) {
    args.IsValid=true;
    return;
  } else {
    args.IsValid=false;
    return;
  }
}
</SCRIPT>


Add an extra attribute to the customvalidator
<asp:CustomValidator ID="valBeginDate" runat="server" ClientValidationFunction="ValidateDate"
   ControlToValidate="txtBeginDate"></asp:CustomValidator>

That should do...
When the function rejects the arguments as invalid no postback will occur. And no databinding or what so ever that happens server-sided.

kGenius
 
 
0
 
kGeniusCommented:
I did some homework for you:

create This Customvalidator: <asp:CustomValidator ID="valBeginDate" runat="server" ClientValidationFunction="ValidateDate" ControlToValidate="txtBeginDate"></asp:CustomValidator>


Add this javascript to your header: (this one checks if a date is in mm/dd/yyyy format)
This works perfect with me...


<script language="javascript">

// Declaring valid date character, minimum year and maximum year
var dtCh= "/";
var minYear=1900;
var maxYear=2100;

function isInteger(s){
      var i;
    for (i = 0; i < s.length; i++){  
        // Check that current character is number.
        var c = s.charAt(i);
        if (((c < "0") || (c > "9"))) return false;
    }
    // All characters are numbers.
    return true;
}

function stripCharsInBag(s, bag){
      var i;
    var returnString = "";
    // Search through string's characters one by one.
    // If character is not in bag, append to returnString.
    for (i = 0; i < s.length; i++){  
        var c = s.charAt(i);
        if (bag.indexOf(c) == -1) returnString += c;
    }
    return returnString;
}

function daysInFebruary (year){
      // February has 29 days in any year evenly divisible by four,
    // EXCEPT for centurial years which are not also divisible by 400.
    return (((year % 4 == 0) && ( (!(year % 100 == 0)) || (year % 400 == 0))) ? 29 : 28 );
}
function DaysArray(n) {
      for (var i = 1; i <= n; i++) {
            this[i] = 31
            if (i==4 || i==6 || i==9 || i==11) {this[i] = 30}
            if (i==2) {this[i] = 29}
   }
   return this
}

function isDate(dtStr){
      var daysInMonth = DaysArray(12)
      var pos1=dtStr.indexOf(dtCh)
      var pos2=dtStr.indexOf(dtCh,pos1+1)
      var strMonth=dtStr.substring(0,pos1)
      var strDay=dtStr.substring(pos1+1,pos2)
      var strYear=dtStr.substring(pos2+1)
      strYr=strYear
      if (strDay.charAt(0)=="0" && strDay.length>1) strDay=strDay.substring(1)
      if (strMonth.charAt(0)=="0" && strMonth.length>1) strMonth=strMonth.substring(1)
      for (var i = 1; i <= 3; i++) {
            if (strYr.charAt(0)=="0" && strYr.length>1) strYr=strYr.substring(1)
      }
      month=parseInt(strMonth)
      day=parseInt(strDay)
      year=parseInt(strYr)
      if (pos1==-1 || pos2==-1){
            return false
      }
      if (strMonth.length<1 || month<1 || month>12){
            return false
      }
      if (strDay.length<1 || day<1 || day>31 || (month==2 && day>daysInFebruary(year)) || day > daysInMonth[month]){
            return false
      }
      if (strYear.length != 4 || year==0 || year<minYear || year>maxYear){
            return false
      }
      if (dtStr.indexOf(dtCh,pos2+1)!=-1 || isInteger(stripCharsInBag(dtStr, dtCh))==false){
            return false
      }
return true
}

function ValidateDate(sender, args){
alert(args.Value);
      if (isDate(args.Value)==false){
            args.IsValid=false;
            return;
      }
    args.IsValid=true;
            return;
 }
</script>
0
 
kGeniusCommented:
just one last correction you should remove "alert(args.Value);" in the javascript (in ValidateDate function).
That one was for testing
kGenius
0

Featured Post

Concerto Cloud for Software Providers & ISVs

Can Concerto Cloud Services help you focus on evolving your application offerings, while delivering the best cloud experience to your customers? From DevOps to revenue models and customer support, the answer is yes!

Learn how Concerto can help you.

  • 4
Tackle projects and never again get stuck behind a technical roadblock.
Join Now