Faraz Shah Khan

Javascript Enable/Disable Dropdown in Gridview using Checkboxes

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 ----------------------------------

<script type="text/javascript">
        function StatusGridDropdown(drpdown)
        {
            document.getElementById(drpdown).disabled = !document.getElementById(drpdown).disabled;
        }
</script>
.
.
.
<asp:GridView ID="GridView1" runat="server" DataSourceID="SqlDataSource1" Width="400px">
        <Columns>
            <asp:TemplateField>
                <AlternatingItemTemplate>
                    <asp:CheckBox ID="cbStatus" runat="server" />
                </AlternatingItemTemplate>
                <ItemTemplate>
                    <asp:CheckBox ID="cbStatus" runat="server" />
                </ItemTemplate>
            </asp:TemplateField>
            <asp:TemplateField>
                <AlternatingItemTemplate>
                    <asp:DropDownList ID="ddl" runat="server" Enabled="False" Width="169px">
                    </asp:DropDownList>
                </AlternatingItemTemplate>
                <ItemTemplate>
                    <asp:DropDownList ID="ddl" runat="server" Width="169px" Enabled="False">
                    </asp:DropDownList>
                </ItemTemplate>
            </asp:TemplateField>
        </Columns>
</asp:GridView>

----------------------------------.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("cbStatus"), CheckBox).Attributes.Add("onclick", "javascript:StatusGridDropdown('" & DirectCast(e.Row.FindControl("ddl"), DropDownList).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("cbStatus")).Attributes.Add("onclick", "javascript:StatusGridDropdown('" + ((DropDownList)e.Row.FindControl("ddl")).ClientID + "')");
    }
}

Reading file content from different webserver using HttpWebRequest

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

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 ---

<script type="text/javascript">
        function OpenPopup()
        {
            window.open("popup.aspx","List","scrollbars=no,resizable=no,width=400,height=280");
            return false;
        }
</script>
.
.
.
<asp:TextBox ID="txtPopupValue" runat="server" Width="327px"></asp:TextBox>
    <asp:Button ID="Button1" runat="server" Text="Show List" />

--- .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 ---

<script language="javascript">
        function GetRowValue(val)
        {
            window.opener.document.getElementById("ctl00_ContentPlaceHolder1_TextBox2").value = val; //hardcoded value used to minimize the code. ControlID can be passed as query string to the popup window
            window.close();
        }
</script>
.
.
.
<asp:GridView ID="GridView1" runat="server" DataSourceID="SqlDataSource1" Width="400px" AllowPaging="True">
            <Columns>
                <asp:TemplateField>
                    <AlternatingItemTemplate>
                        <asp:Button ID="btnSelect" runat="server" Text="Select" />
                    </AlternatingItemTemplate>
                    <ItemTemplate>
                        <asp:Button ID="btnSelect" runat="server" Text="Select" />
                    </ItemTemplate>
                </asp:TemplateField>
            </Columns>
        </asp:GridView>

--- .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

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

    <script type="text/javascript">
        function ShowTime()
        {
            var dt = new Date();
            document.getElementById("<%= TextBox1.ClientID %>").value = dt.toLocaleTimeString();
            window.setTimeout("ShowTime()", 1000);
        }
       
            
    </script>

<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

Personalization Scope