protected void sendButton_Click(object sender, EventArgs e) { alertUserMessage.Text = ""; string receiverID = receiverIDTextBox.Text.Trim(); string senderID = senderIDTextBox.Text.Trim(); string message = messageTextBox.Text.Trim(); if (receiverID.Length == 0 || senderID.Length == 0 || message.Length == 0) { alertUserMessage.Text = "Please enter a valid receiver ID, sender ID and a non blank message"; return; } MsgService.MessagingServiceClient service = new MsgService.MessagingServiceClient(); service.sendMessage(senderID, receiverID, message); alertUserMessage.Text = "Message sent!"; }