Refer the below sample code and implement it as per your code logic.
HTML
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title></title>
<script type="text/javascript">
function setCursorPosition(element, pos) {
var ctrl = document.getElementById(element);
if (ctrl.setSelectionRange) {
ctrl.focus();
ctrl.setSelectionRange(pos, pos);
}
else if (ctrl.createTextRange) {
var range = ctrl.createTextRange();
range.collapse(true);
range.moveEnd('character', pos);
range.moveStart('character', pos);
range.select();
}
}
</script>
</head>
<body>
<form id="form1" runat="server">
<div>
Search <asp:TextBox ID="txtSearch" runat="server" OnTextChanged="txtSearch_TextChanged"
AutoPostBack="true"></asp:TextBox><br />
<asp:Button Text="Submit" runat="server" />
</div>
</form>
</body>
</html>
C#
protected void txtSearch_TextChanged(object sender, EventArgs e)
{
var position = txtSearch.Text.IndexOf(txtSearch.Text) + txtSearch.Text.Length + 1;
var script = String.Format("setCursorPosition('{0}',{1});", txtSearch.ClientID, position);
ClientScript.RegisterStartupScript(GetType(), "CursorScript", script, true);
}
VB.Net
Protected Sub txtSearch_TextChanged(ByVal sender As Object, ByVal e As EventArgs)
Dim position = txtSearch.Text.IndexOf(txtSearch.Text) + txtSearch.Text.Length + 1
Dim script = String.Format("setCursorPosition('{0}',{1});", txtSearch.ClientID, position)
ClientScript.RegisterStartupScript([GetType](), "CursorScript", script, True)
End Sub
Screenshot
