CODEWITHSUNDEEP
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Renaud is Not Bill Gates
Renaud is Not Bill Gates

Reputation: 2084

Unable to cast object of type 'System.Windows.Forms.Button' to type > 'System.Windows.Forms.TextBox'

I wrote a function that empty all TextBox in my form:

Private Sub effacer()
        For Each t As TextBox In Me.Controls
            t.Text = Nothing
        Next
    End Sub

But I had this problem :

Unable to cast object of type 'System.Windows.Forms.Button' to type 'System.Windows.Forms.TextBox'.

I tried to add this If TypeOf t Is TextBox Then but I had the same problem

Upvotes: 1

Views: 9416

Answers (3)

Vadzim Savenok
Vadzim Savenok

Reputation: 940

Here is a line of code that will clear all radioButtons from the groupBox, which is attached to the button_click:

groupBoxName.Controls.OfType<RadioButton>().ToList().ForEach(p => p.Checked = false);

Use appropriate changes to adapt it to your needs.

Upvotes: 0

Tim Schmelter
Tim Schmelter

Reputation: 460108

The Controls collection contains all controls of the form not only TextBoxes.

Instead you can use Enumerable.OfType to find and cast all TextBoxes:

For Each txt As TextBox In Me.Controls.OfType(Of TextBox)()
    txt.Text = ""
Next

If you want to do the same in the "old-school" way:

For Each ctrl As Object In Me.Controls
    If TypeOf ctrl Is TextBox
        DirectCast(ctrl, TextBox).Text = ""
    End If
Next

Upvotes: 5

SLaks
SLaks

Reputation: 887453

For Each t As TextBox In Me.Controls

This line right here tries to cast each control to TextBox.
You need to change that to As Control, or use Me.Controls.OfType(Of TextBox)() to filter the collection before iterating it.

Upvotes: 2

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