If else statement in vB.NET

Question

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Hello,

I know it must so simple but I am missing something silly which I couldn't figure out.
So Here I have search button with Txtbox1 and FromDate and ToDate

Either Txtbox1 should be filled or FromDate and ToDate (both dates) should be filled. Then only Search code should proceed and display the result. Otherwise it should pop up saying enter search criteria.

Can anyone here help me if this silly logic with if else in VB.NET?

Moved from comment

VB

If Not (txtSInvoice IsNot String.Empty) Or Not (txtFromDate IsNot String.Empty AndAlso txtToDate IsNot String.Empty) Then

ScriptManager.RegisterClientScriptBlock(TryCast(sender, Control), Me.GetType(), "alert", "Hello Search", True)
Else
ScriptManager.RegisterClientScriptBlock(TryCast(sender, Control), Me.GetType(), "alert", "Please enter Criteria for Search", True)

End If

I tried this but it doesn't work. I don't know about VB. But in C# it does what you said "txt1 or (frmDate and Todate)"

Posted 13-Jan-15 10:13am

sudevsu

Updated 13-Jan-15 10:29am

PIEBALDconsult

v2

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Maciej Los 13-Jan-15 16:21pm

What have you tried?

sudevsu 13-Jan-15 16:25pm

If Not (txtSInvoice IsNot String.Empty) Or Not (txtFromDate IsNot String.Empty AndAlso txtToDate IsNot String.Empty) Then

ScriptManager.RegisterClientScriptBlock(TryCast(sender, Control), Me.GetType(), "alert", "Hello Search", True)
Else
ScriptManager.RegisterClientScriptBlock(TryCast(sender, Control), Me.GetType(), "alert", "Please enter Criteria for Search", True)

End If

sudevsu 13-Jan-15 16:28pm

I tried this also
If (txtSInvoice.Text.Length > 0) Or (txtFromDate IsNot String.Empty AndAlso txtToDate IsNot String.Empty) Then

Tomas Takac 13-Jan-15 16:46pm

The logic looks fine. Try using String.IsNullOrEmpty[^] or even String.IsNullOrWhiteSpace[^] methods to check for empty values.

sudevsu 14-Jan-15 9:39am

Thank you Tom. This is below code that I changed and it works fine now.

If (txtSInvoice.Text.Length > 0) Or Not (String.IsNullOrEmpty(txtFromDate.Text) AndAlso String.IsNullOrEmpty(txtToDate.Text)) Then

ScriptManager.RegisterClientScriptBlock(TryCast(sender, Control), Me.GetType(), "alert", "Hello Search", True)
Else
ScriptManager.RegisterClientScriptBlock(TryCast(sender, Control), Me.GetType(), "alert", "Please enter Criteria for Search", True)

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PIEBALDconsult · Accepted Answer · 2015-01-13T10:24:00

Solution 1

Quote:
it should pop

Is that what your users want? I wouldn't.

Better to have the Search button disabled until criteria have been entered.

I'm not familiar enough with what you're doing, but how about something like:
searchbutton.Enabled = Txtbox1.Length>0 or ( FromDate... and ToDate... )

Posted 13-Jan-15 10:24am

PIEBALDconsult

Comments

PIEBALDconsult 13-Jan-15 16:30pm

I think you have too many nots in there.

sudevsu 13-Jan-15 16:32pm

Yeah if I don't say Not still it goes in so I tried placing a not

Maciej Los · Accepted Answer · 2015-01-13T10:26:00

Solution 2

Hey, don't be lazy! Try it: If...Then...Else Statement (Visual Basic)[^]

In pseudo-code:

If TextBox is not empty then
   Procceed
Else
   DisplayMessage
End If

Posted 13-Jan-15 10:26am

Maciej Los

Comments

sudevsu 13-Jan-15 16:30pm

I try the same way but it doesn't work.
If (txtSInvoice.Text.Length > 0) Or (txtFromDate IsNot String.Empty AndAlso txtToDate IsNot String.Empty) Then

If I don't give any criteria, still search code proceeds instead of display message.

sudevsu 13-Jan-15 16:35pm

Nothing is there to be lazy in here. But I just don't get the point of two conditions in one if with Or and And in VB.NET.

bojammis · Accepted Answer · 2015-01-13T11:40:00

Solution 4

hi sudevsu,
Marciej has a good point, you should step through your code and test the values independently so that you get a good idea on how to use Boolean operators correctly (Hint - first NOT is a problem).

regs ron O.

Posted 13-Jan-15 11:40am

bojammis

sudevsu · Accepted Answer · 2015-01-14T03:40:00

Based on Tomas advice. I made this working. Thanks to all the guys who helped in this.

VB

If (txtSInvoice.Text.Length > 0) Or Not (String.IsNullOrEmpty(txtFromDate.Text) AndAlso String.IsNullOrEmpty(txtToDate.Text)) Then

              ScriptManager.RegisterClientScriptBlock(TryCast(sender, Control), Me.GetType(), "alert", "Hello Search", True)
          Else
              ScriptManager.RegisterClientScriptBlock(TryCast(sender, Control), Me.GetType(), "alert", "Please enter Criteria for Search", True)

If else statement in vB.NET

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