C#

if (!(string.IsNullOrEmpty(textBox1.Text) ^ string.IsNullOrEmpty(textBox2.Text)))
{
    MessageBox.Show("Valid");
}
else
{
    MessageBox.Show("Invalid");
}

aspdotnetdev wrote:

but this is probably the most succint technique

MessageBox.Show((textBox1.Text.Length==0)==(textBox2.Text.Length==0)?"Valid":"Invalid");

MessageBox.Show((textBox1.Text.Length>0)==(textBox2.Text.Length>0)?"Valid":"Invalid");

MessageBox.Show(((tb1.Text.Length>0)==(tb2.Text.Length>0)?"V":"Inv")+"alid");

MessageBox.Show((tb1.Text.Length>0)==(tb2.Text.Length>0)?"OK":"!OK");

((a.L>0)==(b.L>0)).S();

T

A

if((!String.IsNullOrEmpty(BP_S.Text) && !String.IsNullOrEmpty(BP_D.Text)) || (String.IsNullOrEmpty(BP_S.Text) && String.IsNullOrEmpty(BP_D.Text)))

harold aptroot wrote:

he never said anything about that

D S result
0 0 1
0 1 1
1 0 0
1 1 1

harold aptroot wrote:

The OP should reply and clear this up

jrahma wrote:

if the user entered BP_S then he MUST enter BP_D
similarly, if the user entered BP_D then he MUST enter BP_S

but user can leave both BP_S and BP_D as NULL

jrahma wrote:

if the user entered BP_S then he MUST enter BP_D

If the first textbox contains some text, the second textbox must contain some text.

jrahma wrote:

if the user entered BP_D then he MUST enter BP_S

If the second textbox contains some text, the first textbox must contain some text.

jrahma wrote:

user can leave both BP_S and BP_D as NULL

If both are empty, that is fine.