Copiar contenido TextBox

Clipboard.SetText(tb_conex.Text.Trim)

cambiar fondo textbox

TextBox1.BackColor = System.Drawing.SystemColors.Info

Mostrar contraseña TextBox

Public Class clave

    Private passChar As Char = "?"

    Private Sub clave_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        TBclave.PasswordChar = passChar
    End Sub

    Private Sub CBclave_CheckedChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles CBclave.CheckedChanged
        If CBclave.Checked Then
            TBclave.PasswordChar = ""
        Else
            TBclave.PasswordChar = passChar
        End If
    End Sub

End Class

Cursor del mouse desaparece al escribir en TextBox RichTextBox

Private Sub TextBox_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles tbRutEmpresa.TextChanged
        Me.Cursor = Cursors.Default
    End Sub

    Private Sub TextBox_MouseEnter(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles tbRutEmpresa.MouseEnter
        Me.Cursor = Cursors.Default
    End Sub

    Private Sub TextBox_MouseLeave(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles tbRutEmpresa.MouseLeave
        Me.Cursor = Cursors.Default
    End Sub


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Bloquear un caracter TextBox

Private Sub tbtexto_KeyPress(ByVal sender As System.Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles tbtexto.KeyPress
        If e.KeyChar = ";" Then
            e.Handled = True
        End If
    End Sub

Validar números TextBox

If String.IsNullOrEmpty(tbnumber.Text.Trim("0")) Then
            tbnumber.Clear()
            MessageBox.Show("Ingrese un valor mayor que cero")

            Exit Sub
        Else
            Dim number As Long = 0
            Dim result As Boolean = Int64.TryParse(tbnumber.Text.Trim, number)

            If Not result Then
                MessageBox.Show("Número no válido")
            Else
                tbnumber.Text = tbnumber.Text.TrimStart("0")
            End If

            MessageBox.Show(result)
        End If

Deshabilitar copiar-pegar en un TextBox

Propiedades
ShortcutsEnabled = False

Desactivar cursor en un TextBox

TextBox1.Enabled = False
TextBox1.Enabled = True

no copiar,pegar,seleccionar en TextBox

ShortcutsEnabled = False

Bloquear cursor TextBox

Imports System.Runtime.InteropServices

Public Class general

    <DllImport("user32")> _
    Private Shared Function HideCaret(ByVal hWnd As IntPtr) As Integer
    End Function

    Private Sub TextBox1_GotFocus(ByVal sender As Object, ByVal e As System.EventArgs) Handles TextBox1.GotFocus
        HideCaret(TextBox1.Handle)
    End Sub

    Private Sub general_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        TextBox1.Cursor = Cursors.Arrow
    End Sub
End Class

Limpiar un TextBox

TextBox1.Clear()

Aceptar sólo números en un Textbox y otro caracter

Private Sub tbfecha_KeyPress(ByVal sender As System.Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles tbfecha.KeyPress
        If Not Char.IsControl(e.KeyChar) AndAlso Not Char.IsDigit(e.KeyChar) AndAlso (e.KeyChar <> "-") Then
            e.Handled = True
        End If
    End Sub

Aceptar sólo números en un TextBox

Private Sub tbrut_KeyPress(ByVal sender As System.Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles tbrut.KeyPress
        If Not Char.IsControl(e.KeyChar) AndAlso Not Char.IsDigit(e.KeyChar) Then
            e.Handled = True
        End If

    End Sub

Deshabilitar clic derecho del mouse en un TextBox

Private Sub tbrut_MouseDown(ByVal sender As System.Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles tbrut.MouseDown
        tbrut.ContextMenu = New ContextMenu()
    End Sub

Insert texto siempre al principio de un textbox

textbox1.Text = textbox1.Text.Insert(0, "Iniciando captura " & i & Environment.NewLine)

Bloquear TextBox sin cursor

Private Sub TextBox_Enter(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles tb_ruta.Enter
        TextBox1.Enabled = False
        TextBox1.Enabled = True
    End Sub

Bloquear TextBox multilínea tecla Supr

Private Sub TextBox2_KeyDown(ByVal sender As System.Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles TextBox2.KeyDown
        e.SuppressKeyPress = True
    End Sub