Develop Reference

TextChanged Event is not firing

In my single web application, only the Page_Load(...) event is firing. I've tried using the text change event below (auto generated by double clicking the textbox):
protected void txtBuyerExtension_TextChanged(object sender, EventArgs e)
{
// do something
}
But nothing happens. It does that for every control... the only event that fires is Page_Load. How come it is doing this?

Add AutoPostBack="True"
<asp:TextBox ID="txtBuyerExtension" runat="server" OnTextChanged="txtBuyerExtension_TextChanged" AutoPostBack="True"></asp:TextBox>

You need to set the AutoPostBack property to enable TextChange event.
<asp:TextBox ID="txtBuyerExtension" runat="server" OnTextChanged="txtBuyerExtension_TextChanged" AutoPostBack="True"></asp:TextBox>
And once you change the focus from TextBox this event will fire.

<asp:TextBox ID="txtSearch" CssClass="textbox1" placeholder="Search.." AutoPostBack="true" runat="server"
OnTextChanged="txtSearch_TextChanged"></asp:TextBox>

ASP C# RequiredFieldValidator

[textbox1]
[textbox2]
[button1] [linkbutton1]
i have 2 textboxes, 2 RequiredFieldValidator, button1 and linkbutton.
the button1 and 2textboxes are working properly with RequiredFieldValidator, but if i click the linkbutton the RequiredFieldValidator also appears.
I want the RequiredFieldValidator focus only in button1. Is this possible?

Set CausesValidation="false" in your link button markup like this
<asp:LinkButton ID="lnkButton" runat="server" CausesValidation="false"></asp:LinkButton>

you need to specify Validation Groups
<asp:requiredfieldvalidator id="RequiredFieldValidator2"
controltovalidate="AgeTextBox"
validationgroup="PersonalInfoGroup"
errormessage="Enter your age."
runat="Server">
</asp:requiredfieldvalidator>

Use ValidationGroup property of RequiredFieldValidator.
Set the ValidataionGroup="someName" for your textbox1-requiredfieldvalidator, textbox2- requiredfieldvalidator and your button1 control.
Note: Keep the name of the ValidationGroup same.

Call Server Side function with Keyup Event in Asp.Net

I have a TextBox and I want to capture the Keyup in the Textbox and get the TextBox value at the Code Behind File and Bind The GridView with the Input Received from the TextBox.
I don't want to use Text_Change Event of Asp.net. i want that when ever user enter anything in the TextBox, that value should go to code behind and bind the grid by calling BindGrid Function
<asp:TextBox ID="txtSearch" runat="server"></asp:TextBox>
protected void BindGrid(string searchvalue)
{
// i want the txtSearch value over here.
}

You need to use asp.net ajax. Putting your button and grid in UpdatePanel will update the gridview after binding on button click.
In html
<asp:UpdatePanel runat="server" ID="updatePanel">
<asp:TextBox runat="server" ID="search"
ClientIDMode="Static" OnKeyUp="refreshPanel(this);" />
In javascript
function refreshPanel(textbox) {
alert(this.value)
__doPostBack('<%= updatePanel.UniqueID %>', this.value);
}
In code behind
string parameter = Request["__EVENTARGUMENT"];

Fire SelectedIndexChanged event on button click for dropdown

i change dropdown list with button click like this:
ddl.selectedIndex+=1
my ddl has a SelectedIndexChanged event which is not firing if index changed through button. Is it a normal behavior? Should I create separate method and call it right after the ddl.selectedIndex+=1 or there's a better way?

I'm assuming you're using ASP.NET? If so, setting AutoPostBack may help:
<asp:DropDownList ID="ddl" runat="server" AutoPostBack="true">
</asp:DropDownList>

Validation in imagebutton, button not occuring

In my project, validation is not occurring at button_click and imagebutton_click. Why could it be so?
I also gave same validation group to all validators and button and also CAUSEVALIDATION "true" in button
Please help solve this.

Add validation group to image button too and check. Also check if your image button has image in it. Other wise it will not fire events
**
<asp:TextBox ID="txt_password" runat="server" CssClass="text_box_password" TextMode="Password" Width="180px"></asp:TextBox>
<asp:RequiredFieldValidator ID="RequiredFieldValidator2" runat="server" ControlToValidate="txt_password" ErrorMessage="*" ValidationGroup="aaaa">**</asp:RequiredFieldValidator>
**