catching empty values in text boxes

[Err]

How can I catch empty values on 3 text boxes that need values.I have three text boxes: txtGrade1, txtGrade2 and txtGrade3.and I have a label for any message.This is for a simple calculator that I'm working on, if you need more code on this, then please say so.

If txtGrade1.Text = "" Or txtGrade2.Text = "" Or txtGrade3.Text = "" Then	  lblMsg.Text = "Numbers must be inputed to all 3 boxes."End If

[aspnetguy]

I have read that checking to to see if a string = "" is not a good practice (not sure why). There are 3 other methods you can try.

If txtGrade1.Text = String.Empty Then

If txtGrade1.Text.Length < 1  Then

If String.Compare(txtGrade1.Text,String.Empty) = 0 Then

Does the code you posted not work. It seems to me that it should. You can also try one of the methods I posted.

[jesh]

I recently found another method:

if(String.IsNullOrEmpty(txtGrade1.Text)){}

EDIT: Of course, my sample is in C#...

[aspnetguy]

I recently found another method:

if(String.IsNullOrEmpty(txtGrade1.Text)){}

EDIT: Of course, my sample is in C#...which is the best language in the world! IMO

[Err]

Cool. I'll be sure to try that, I'm working on this at school since I still don't have the program for it. No it doesn't work with the above code I posted. I also tried putting all 3 boxes in separate If statements, but that didn't work either.

[aspnetguy]

you can download Visual Web Developer Express for free. It is a stripped down "for web" version of Visual Studio 2005.

[pulpfiction]

you can also use validator controls to check empty textbox, "requiredfieldvalidator"http://www.w3schools.com/aspnet/control_re...ldvalidator.asp

[Err]

It's still not working, please look at my code and tell me where I went wrong.

Public Class Form1Private Sub btnExit_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnExit.Click        Me.Close()    End Sub    Private Sub btnClear_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnClear.Click        txtGrade1.Clear()        Me.txtGrade2.Clear()        Me.txtGrade3.Clear()        lblLetter.ResetText()        'lblAvg.Text = ""        lblAvg.ForeColor = Color.Empty        lblAvg.BackColor = Color.Empty        lblAvg.ResetText()        lblMsg.ResetText()        txtName.ResetText()        txtAbs.ResetText()        lblAvg.BackColor = Color.White        txtGrade1.Focus()    End Sub    Private Sub btnCalculate_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnCalculate.Click        Dim shoGrade1 As Short = 0        Dim shoGrade2 As Short        Dim shoGrade3 As Short        Dim sngAvg As Single        'Input        shoGrade1 = Val(txtGrade1.Text)        shoGrade2 = Val(txtGrade2.Text)        shoGrade3 = Val(txtGrade3.Text)        'Processing        sngAvg = (shoGrade1 + shoGrade2 + shoGrade3) / 3        'If Not IsNumeric(txtGrade1.Text) Then        'lblMsg.Text = "Please enter numbers only."        'End If        If String.Compare(txtGrade1.Text, String.Empty) = 0 Then            lblMsg.Text = "Numbers must be inputed for box 1"        End If        'If txtGrade1.Text = "" Or txtGrade2.Text = "" Or txtGrade3.Text = "" Then        'lblMsg.Text = "Numbers must be inputed to all 3 boxes."        'End If        If sngAvg < 0 Then            lblLetter.Text = "X"            lblMsg.Text = "Please enter positive numbers only"        ElseIf sngAvg < 60 Then            lblLetter.Text = "F"            lblMsg.Text = "You are teh fail."            lblAvg.BackColor = Color.Red        ElseIf sngAvg < 70 Then            lblLetter.Text = "D"            lblMsg.Text = "Almost, but you're still a failure."            lblAvg.BackColor = Color.Yellow            lblAvg.ForeColor = Color.Black        ElseIf sngAvg < 80 Then            lblLetter.Text = "C"            lblMsg.Text = "Passing."            lblAvg.BackColor = Color.Yellow        ElseIf sngAvg < 90 Then            lblLetter.Text = "B"            lblMsg.Text = "Good."            lblAvg.BackColor = Color.LightGreen            lblAvg.ForeColor = Color.Black        ElseIf sngAvg <= 100 Then            lblLetter.Text = "A"            lblMsg.Text = "Winnar."            lblAvg.BackColor = Color.Green            lblAvg.ForeColor = Color.FloralWhite        ElseIf sngAvg > 100 Then            lblMsg.Text = "Impossable."        Else            lblLetter.Text = "Invalid"            lblMsg.Text = "Invalid Inputs"        End If        'Output        lblAvg.Text = FormatNumber(sngAvg, 1)        'lblAvg.ForeColor = Color.FloralWhite        'lblAvg.BackColor = Color.Firebrick    End Sub    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load        'lblDate.Text = FormatDateTime(Today, DateFormat.LongDate)        'lblTime.Text = FormatDateTime(Now, DateFormat.ShortTime)        lblDate.Text = Now.ToShortDateString        lblTime.Text = TimeOfDay.ToLongTimeString        'changes color of lblAvg, when the program starts, to white        Me.lblAvg.BackColor = Color.White    End Sub    Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick        lblTime.Text = TimeOfDay.ToLongTimeString    End SubEnd Class

And the Form code:

#Region " Windows Form Designer generated code "    Public Sub New()        MyBase.New()        'This call is required by the Windows Form Designer.        InitializeComponent()        'Add any initialization after the InitializeComponent() call    End Sub    'Form overrides dispose to clean up the component list.    Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean)        If disposing Then            If Not (components Is Nothing) Then                components.Dispose()            End If        End If        MyBase.Dispose(disposing)    End Sub    'Required by the Windows Form Designer    Private components As System.ComponentModel.IContainer    'NOTE: The following procedure is required by the Windows Form Designer    'It can be modified using the Windows Form Designer.      'Do not modify it using the code editor.    Friend WithEvents Label1 As System.Windows.Forms.Label    Friend WithEvents Label2 As System.Windows.Forms.Label    Friend WithEvents Label3 As System.Windows.Forms.Label    Friend WithEvents Label4 As System.Windows.Forms.Label    Friend WithEvents Label5 As System.Windows.Forms.Label    Friend WithEvents txtGrade1 As System.Windows.Forms.TextBox    Friend WithEvents txtGrade2 As System.Windows.Forms.TextBox    Friend WithEvents txtGrade3 As System.Windows.Forms.TextBox    Friend WithEvents lblAvg As System.Windows.Forms.Label    Friend WithEvents btnExit As System.Windows.Forms.Button    Friend WithEvents btnClear As System.Windows.Forms.Button    Friend WithEvents btnCalculate As System.Windows.Forms.Button    Friend WithEvents GroupBox1 As System.Windows.Forms.GroupBox    Friend WithEvents lblDate As System.Windows.Forms.Label    Friend WithEvents lblTime As System.Windows.Forms.Label    Friend WithEvents Timer1 As System.Windows.Forms.Timer    Friend WithEvents lblMsg As System.Windows.Forms.Label    Friend WithEvents lblLetter As System.Windows.Forms.Label    Friend WithEvents Label7 As System.Windows.Forms.Label    Friend WithEvents txtAbs As System.Windows.Forms.TextBox    Friend WithEvents Label6 As System.Windows.Forms.Label    Friend WithEvents txtName As System.Windows.Forms.TextBox    Friend WithEvents Label8 As System.Windows.Forms.Label    <System.Diagnostics.DebuggerStepThrough()> Private Sub InitializeComponent()        Me.components = New System.ComponentModel.Container        Me.Label1 = New System.Windows.Forms.Label        Me.Label2 = New System.Windows.Forms.Label        Me.Label3 = New System.Windows.Forms.Label        Me.Label4 = New System.Windows.Forms.Label        Me.Label5 = New System.Windows.Forms.Label        Me.txtGrade1 = New System.Windows.Forms.TextBox        Me.txtGrade2 = New System.Windows.Forms.TextBox        Me.txtGrade3 = New System.Windows.Forms.TextBox        Me.lblAvg = New System.Windows.Forms.Label        Me.btnExit = New System.Windows.Forms.Button        Me.btnClear = New System.Windows.Forms.Button        Me.btnCalculate = New System.Windows.Forms.Button        Me.GroupBox1 = New System.Windows.Forms.GroupBox        Me.lblTime = New System.Windows.Forms.Label        Me.lblDate = New System.Windows.Forms.Label        Me.Timer1 = New System.Windows.Forms.Timer(Me.components)        Me.lblMsg = New System.Windows.Forms.Label        Me.lblLetter = New System.Windows.Forms.Label        Me.Label7 = New System.Windows.Forms.Label        Me.txtAbs = New System.Windows.Forms.TextBox        Me.Label6 = New System.Windows.Forms.Label        Me.txtName = New System.Windows.Forms.TextBox        Me.Label8 = New System.Windows.Forms.Label        Me.GroupBox1.SuspendLayout()        Me.SuspendLayout()        '        'Label1        '        Me.Label1.AutoSize = True        Me.Label1.Font = New System.Drawing.Font("Comic Sans MS", 14.25!, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, CType(0, Byte))        Me.Label1.Location = New System.Drawing.Point(56, 16)        Me.Label1.Name = "Label1"        Me.Label1.Size = New System.Drawing.Size(225, 30)        Me.Label1.TabIndex = 0        Me.Label1.Text = "Letter Grade Calculator"        Me.Label1.TextAlign = System.Drawing.ContentAlignment.MiddleCenter        '        'Label2        '        Me.Label2.Location = New System.Drawing.Point(16, 144)        Me.Label2.Name = "Label2"        Me.Label2.Size = New System.Drawing.Size(72, 32)        Me.Label2.TabIndex = 4        Me.Label2.Text = "Grade &1:"        Me.Label2.TextAlign = System.Drawing.ContentAlignment.MiddleRight        '        'Label3        '        Me.Label3.Location = New System.Drawing.Point(16, 280)        Me.Label3.Name = "Label3"        Me.Label3.Size = New System.Drawing.Size(72, 32)        Me.Label3.TabIndex = 10        Me.Label3.Text = "Average:"        Me.Label3.TextAlign = System.Drawing.ContentAlignment.MiddleRight        '        'Label4        '        Me.Label4.Location = New System.Drawing.Point(16, 232)        Me.Label4.Name = "Label4"        Me.Label4.Size = New System.Drawing.Size(72, 32)        Me.Label4.TabIndex = 8        Me.Label4.Text = "Grade &3:"        Me.Label4.TextAlign = System.Drawing.ContentAlignment.MiddleRight        '        'Label5        '        Me.Label5.Location = New System.Drawing.Point(16, 192)        Me.Label5.Name = "Label5"        Me.Label5.Size = New System.Drawing.Size(72, 32)        Me.Label5.TabIndex = 6        Me.Label5.Text = "Grade &2:"        Me.Label5.TextAlign = System.Drawing.ContentAlignment.MiddleRight        '        'txtGrade1        '        Me.txtGrade1.Location = New System.Drawing.Point(112, 144)        Me.txtGrade1.Name = "txtGrade1"        Me.txtGrade1.Size = New System.Drawing.Size(72, 28)        Me.txtGrade1.TabIndex = 5        Me.txtGrade1.Text = ""        '        'txtGrade2        '        Me.txtGrade2.Location = New System.Drawing.Point(112, 192)        Me.txtGrade2.Name = "txtGrade2"        Me.txtGrade2.Size = New System.Drawing.Size(72, 28)        Me.txtGrade2.TabIndex = 7        Me.txtGrade2.Text = ""        '        'txtGrade3        '        Me.txtGrade3.Location = New System.Drawing.Point(112, 240)        Me.txtGrade3.Name = "txtGrade3"        Me.txtGrade3.Size = New System.Drawing.Size(72, 28)        Me.txtGrade3.TabIndex = 9        Me.txtGrade3.Text = ""        '        'lblAvg        '        Me.lblAvg.BorderStyle = System.Windows.Forms.BorderStyle.Fixed3D        Me.lblAvg.Location = New System.Drawing.Point(112, 280)        Me.lblAvg.Name = "lblAvg"        Me.lblAvg.Size = New System.Drawing.Size(72, 28)        Me.lblAvg.TabIndex = 0        Me.lblAvg.TextAlign = System.Drawing.ContentAlignment.MiddleRight        '        'btnExit        '        Me.btnExit.Location = New System.Drawing.Point(272, 384)        Me.btnExit.Name = "btnExit"        Me.btnExit.Size = New System.Drawing.Size(88, 32)        Me.btnExit.TabIndex = 13        Me.btnExit.Text = "E&xit"        '        'btnClear        '        Me.btnClear.Location = New System.Drawing.Point(152, 384)        Me.btnClear.Name = "btnClear"        Me.btnClear.Size = New System.Drawing.Size(88, 32)        Me.btnClear.TabIndex = 12        Me.btnClear.Text = "Clea&r"        '        'btnCalculate        '        Me.btnCalculate.Location = New System.Drawing.Point(40, 384)        Me.btnCalculate.Name = "btnCalculate"        Me.btnCalculate.Size = New System.Drawing.Size(88, 32)        Me.btnCalculate.TabIndex = 11        Me.btnCalculate.Text = "&Calculate"        '        'GroupBox1        '        Me.GroupBox1.Controls.Add(Me.lblTime)        Me.GroupBox1.Controls.Add(Me.lblDate)        Me.GroupBox1.Location = New System.Drawing.Point(216, 104)        Me.GroupBox1.Name = "GroupBox1"        Me.GroupBox1.Size = New System.Drawing.Size(208, 136)        Me.GroupBox1.TabIndex = 9        Me.GroupBox1.TabStop = False        Me.GroupBox1.Text = "Date and Time"        '        'lblTime        '        Me.lblTime.BorderStyle = System.Windows.Forms.BorderStyle.Fixed3D        Me.lblTime.Location = New System.Drawing.Point(16, 80)        Me.lblTime.Name = "lblTime"        Me.lblTime.Size = New System.Drawing.Size(176, 40)        Me.lblTime.TabIndex = 1        Me.lblTime.TextAlign = System.Drawing.ContentAlignment.MiddleCenter        '        'lblDate        '        Me.lblDate.BorderStyle = System.Windows.Forms.BorderStyle.Fixed3D        Me.lblDate.Location = New System.Drawing.Point(16, 32)        Me.lblDate.Name = "lblDate"        Me.lblDate.Size = New System.Drawing.Size(176, 40)        Me.lblDate.TabIndex = 0        Me.lblDate.TextAlign = System.Drawing.ContentAlignment.MiddleCenter        '        'Timer1        '        Me.Timer1.Enabled = True        Me.Timer1.Interval = 1000        '        'lblMsg        '        Me.lblMsg.Location = New System.Drawing.Point(216, 248)        Me.lblMsg.Name = "lblMsg"        Me.lblMsg.Size = New System.Drawing.Size(208, 80)        Me.lblMsg.TabIndex = 10        Me.lblMsg.TextAlign = System.Drawing.ContentAlignment.MiddleCenter        '        'lblLetter        '        Me.lblLetter.BorderStyle = System.Windows.Forms.BorderStyle.Fixed3D        Me.lblLetter.Location = New System.Drawing.Point(112, 328)        Me.lblLetter.Name = "lblLetter"        Me.lblLetter.Size = New System.Drawing.Size(72, 28)        Me.lblLetter.TabIndex = 12        Me.lblLetter.TextAlign = System.Drawing.ContentAlignment.MiddleRight        '        'Label7        '        Me.Label7.Location = New System.Drawing.Point(16, 328)        Me.Label7.Name = "Label7"        Me.Label7.Size = New System.Drawing.Size(72, 32)        Me.Label7.TabIndex = 11        Me.Label7.Text = "Grade:"        Me.Label7.TextAlign = System.Drawing.ContentAlignment.MiddleRight        '        'txtAbs        '        Me.txtAbs.Location = New System.Drawing.Point(112, 96)        Me.txtAbs.Name = "txtAbs"        Me.txtAbs.Size = New System.Drawing.Size(72, 28)        Me.txtAbs.TabIndex = 3        Me.txtAbs.Text = ""        '        'Label6        '        Me.Label6.Location = New System.Drawing.Point(8, 96)        Me.Label6.Name = "Label6"        Me.Label6.Size = New System.Drawing.Size(80, 32)        Me.Label6.TabIndex = 2        Me.Label6.Text = "&Absences:"        Me.Label6.TextAlign = System.Drawing.ContentAlignment.MiddleRight        '        'txtName        '        Me.txtName.Location = New System.Drawing.Point(112, 48)        Me.txtName.Name = "txtName"        Me.txtName.Size = New System.Drawing.Size(208, 28)        Me.txtName.TabIndex = 1        Me.txtName.Text = ""        '        'Label8        '        Me.Label8.Location = New System.Drawing.Point(16, 48)        Me.Label8.Name = "Label8"        Me.Label8.Size = New System.Drawing.Size(72, 32)        Me.Label8.TabIndex = 0        Me.Label8.Text = "Name:"        Me.Label8.TextAlign = System.Drawing.ContentAlignment.MiddleRight        '        'Form1        '        Me.AutoScaleBaseSize = New System.Drawing.Size(8, 21)        Me.ClientSize = New System.Drawing.Size(440, 430)        Me.Controls.Add(Me.txtName)        Me.Controls.Add(Me.Label8)        Me.Controls.Add(Me.txtAbs)        Me.Controls.Add(Me.Label6)        Me.Controls.Add(Me.lblLetter)        Me.Controls.Add(Me.Label7)        Me.Controls.Add(Me.lblMsg)        Me.Controls.Add(Me.GroupBox1)        Me.Controls.Add(Me.btnCalculate)        Me.Controls.Add(Me.btnClear)        Me.Controls.Add(Me.btnExit)        Me.Controls.Add(Me.lblAvg)        Me.Controls.Add(Me.txtGrade3)        Me.Controls.Add(Me.txtGrade2)        Me.Controls.Add(Me.txtGrade1)        Me.Controls.Add(Me.Label5)        Me.Controls.Add(Me.Label4)        Me.Controls.Add(Me.Label3)        Me.Controls.Add(Me.Label2)        Me.Controls.Add(Me.Label1)        Me.Font = New System.Drawing.Font("Comic Sans MS", 11.25!, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, CType(0, Byte))        Me.Name = "Form1"        Me.Text = "Letter Grade Calculator"        Me.GroupBox1.ResumeLayout(False)        Me.ResumeLayout(False)    End Sub#End Region

Edit: I got it, I needed to put "Exit Sub" before my "End If" statements.