how to check if the text box is empty.

Question

Hi.

How can i check the value of text box if it empty or not.

i have 1 combo box and button. the combobox will display project name from data table. and 4 text box txt1, txt2, txt3, and txt4.

i want to do then when i click the button it will pass the value of combo box to the text box. if the txt1 is emty then pass it to txt1, if txt1 not empty pass it to txt2 and so on. can i do that.?

then when selected the item in the combo box and select another it change to "System.Data.DataRowView" and not display the data anymore how can i make it to display the data.

 Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click
        Dim project As String
        project = CStr(ComboBox2.SelectedText)

        If TextBox1.Text = "" Then
            TextBox1.Text = project
        ElseIf TextBox1.Text.Trim <> "" Then
            TextBox2.Text = project
        ElseIf TextBox1.Text.Trim <> "" And TextBox2.Text.Trim <> "" Then
            TextBox3.Text = project
        ElseIf TextBox1.Text.Trim <> "" And TextBox2.Text.Trim <> "" And TextBox3.Text.Trim <> "" Then
            TextBox4.Text = project
        Else
        End If

    End Sub

i make this code. but it does not work.

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~SS~

Answer 1

How can i check the value of text box if it empty or not.

i have 1 combo box and button. the combobox will display project name from data table. and 4 text box txt1, txt2, txt3, and txt4.

i want to do then when i click the button it will pass the value of combo box to the text box. if the txt1 is emty then pass it to txt1, if txt1 not empty pass it to txt2 and so on. can i do that.?

 Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click
        Dim project As String
        project = CStr(ComboBox2.SelectedText)

        If TextBox1.Text = "" Then
            TextBox1.Text = project
        ElseIf TextBox1.Text.Trim <> "" Then
            TextBox2.Text = project
        ElseIf TextBox1.Text.Trim <> "" And TextBox2.Text.Trim <> "" Then
            TextBox3.Text = project
        ElseIf TextBox1.Text.Trim <> "" And TextBox2.Text.Trim <> "" And TextBox3.Text.Trim <> "" Then
            TextBox4.Text = project
        Else
        End If

    End Sub

i make this code. but it does not work.

Rethink your logic. It doesn't appear to match your description.

For example, why do you set TextBox2.Text to project after only
checking if TextBox1.Text is empty? And so on down the line.

According to your description you should only be setting a TextBox to
project if it's empty and no prior TextBoxes are empty. More like this:

If TextBox1.Text = "" Then    
    TextBox1.Text = project   
ElseIf TextBox2.Text = "" Then
    TextBox2.Text = project   
ElseIf TextBox3.Text = "" Then
    TextBox3.Text = project   
ElseIf TextBox4.Text = "" Then
    TextBox4.Text = project   
    ' Else no place to put it!     
End If                        

- Wayne

Answer 2

I think WayneAKing's code is the simplest.

And I'd like to add some.

Dim project As String
project = ComboBox2.Text.Trim	' --<< trim here

Regards,
Ashidacchi

Answer 3

Try this solution too:

Private Sub Button3_Click(sender As Object, e As EventArgs) Handles Button3.Click
    Dim project = ComboBox2.Text
    Dim textboxes = {TextBox1, TextBox2, TextBox3, TextBox4}
    Dim first = textboxes.FirstOrDefault(Function(tb) String.IsNullOrWhiteSpace(tb.Text))
    If first IsNot Nothing Then first.Text = project
End Sub

Answer 4

Thanks... Both code works...Thank You guys...

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~SS~