Question

I’m trying to require the user to enter data in at least one of five textboxes before running a search query. .

I’m getting error messages about

1. converting a string to boolean
   2 “Operator ‘&&’ cannot be applied to operands of type ‘string’ and ‘string'”

   if (txtLoginName.Text=String.Empty && 
       txtDisplayName.Text = String.Empty && 
       txtCode.Text = String.Empty && 
       txtEmailAddress.Text = String.Empty && 
       txtName.Text = String.Empty)
   {
   
       lblErrorMessage.Text = "At least one search criteria is required.";
       return;
   }
   

Answer 1

Try the code below. In your sample you were using “=” instead of “==” in C#.

   if (txtLoginName.Text==String.Empty && 
        txtDisplayName.Text == String.Empty && 
        txtCode.Text == String.Empty && 
        txtEmailAddress.Text == String.Empty && 
        txtName.Text == String.Empty)

Another way to accomplish the same thing would be to use this:

   if (!String.IsNullorEmpty(txtLoginName.Text) && 
        !String.IsNullorEmpty(txtDisplayName.Text) && 
        !String.IsNullorEmpty(txtCode.Text) && 
        !String.IsNullorEmpty(txtEmailAddress.Text) && 
        !String.IsNullorEmpty(txtName.Text))