ContainerControl.ValidateChildren Method
Definition
Important
Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.
Causes all of the child controls within a control that support validation to validate their data.
Overloads
ValidateChildren() |
Causes all of the child controls within a control that support validation to validate their data. |
ValidateChildren(ValidationConstraints) |
Causes all of the child controls within a control that support validation to validate their data. |
ValidateChildren()
Causes all of the child controls within a control that support validation to validate their data.
public:
virtual bool ValidateChildren();
[System.ComponentModel.Browsable(false)]
public virtual bool ValidateChildren ();
[<System.ComponentModel.Browsable(false)>]
abstract member ValidateChildren : unit -> bool
override this.ValidateChildren : unit -> bool
Public Overridable Function ValidateChildren () As Boolean
Returns
true
if all of the children validated successfully; otherwise, false
. If called from the Validating or Validated event handlers, this method will always return false
.
- Attributes
Examples
The following code example turns off implicit validation for a form and all of its contained controls, and instead manually performs validation of all of the form's children when a mouse button is clicked.
using System;
using System.Collections.Generic;
using System.Windows.Forms;
using System.Drawing;
using System.Text;
namespace TestValidation
{
class Form1 : Form
{
private static void Main(string[] args)
{
Application.EnableVisualStyles();
Application.Run(new Form1());
}
private TextBox firstNameBox, lastNameBox;
private Button validateButton;
private FlowLayoutPanel flowLayout1;
private Form1()
{
this.Load += new EventHandler(Form1_Load);
}
void Form1_Load(object sender, EventArgs e)
{
// Turn off validation when a control loses focus. This will be inherited by child
// controls on the form, enabling us to validate the entire form when the
// button is clicked instead of one control at a time.
this.AutoValidate = AutoValidate.Disable;
flowLayout1 = new FlowLayoutPanel();
flowLayout1.Dock = DockStyle.Fill;
flowLayout1.Name = "flowLayout1";
firstNameBox = new TextBox();
firstNameBox.Name = "firstNameBox";
firstNameBox.Size = new Size(75, firstNameBox.Size.Height);
firstNameBox.CausesValidation = true;
firstNameBox.Validating += new System.ComponentModel.CancelEventHandler(firstNameBox_Validating);
flowLayout1.Controls.Add(firstNameBox);
lastNameBox = new TextBox();
lastNameBox.Name = "lastNameBox";
lastNameBox.Size = new Size(75, lastNameBox.Size.Height);
lastNameBox.CausesValidation = true;
lastNameBox.Validating += new System.ComponentModel.CancelEventHandler(lastNameBox_Validating);
flowLayout1.Controls.Add(lastNameBox);
validateButton = new Button();
validateButton.Text = "Validate";
// validateButton.Location = new Point(170, 10);
validateButton.Size = new Size(75, validateButton.Size.Height);
validateButton.Click += new EventHandler(validateButton_Click);
flowLayout1.Controls.Add(validateButton);
this.Controls.Add(flowLayout1);
this.Text = "Test Validation";
}
void firstNameBox_Validating(object sender, System.ComponentModel.CancelEventArgs e)
{
if (firstNameBox.Text.Length == 0)
{
e.Cancel = true;
}
else
{
e.Cancel = false;
}
}
void lastNameBox_Validating(object sender, System.ComponentModel.CancelEventArgs e)
{
e.Cancel = false;
}
void validateButton_Click(object sender, EventArgs e)
{
if (this.ValidateChildren())
{
MessageBox.Show("Validation succeeded!");
}
else
{
MessageBox.Show("Validation failed.");
}
}
}
}
Imports System.Drawing
Imports System.Windows.Forms
Public Class Form1
Inherits Form
'Entry point which delegates to C-style main Private Function
Public Overloads Shared Sub Main()
Main(System.Environment.GetCommandLineArgs())
End Sub
Private Overloads Shared Sub Main(ByVal args() As String)
Application.EnableVisualStyles()
Application.Run(New Form1())
End Sub
Private WithEvents FirstNameBox, LastNameBox As TextBox
Private WithEvents ValidateButton As Button
Private FlowLayout1 As FlowLayoutPanel
Private Sub New()
End Sub
Private Sub Form1_Load(ByVal sender As Object, ByVal e As EventArgs) Handles Me.Load
' Turn off validation when a control loses focus. This will be inherited by child
' controls on the form, enabling us to validate the entire form when the
' button is clicked instead of one control at a time.
Me.AutoValidate = System.Windows.Forms.AutoValidate.Disable
FlowLayout1 = New FlowLayoutPanel()
FlowLayout1.Dock = DockStyle.Fill
FirstNameBox = New TextBox()
FirstNameBox.Name = "FirstNameBox"
FirstNameBox.Location = New Point(10, 10)
FirstNameBox.Size = New Size(75, FirstNameBox.Size.Height)
FirstNameBox.CausesValidation = True
FlowLayout1.Controls.Add(FirstNameBox)
LastNameBox = New TextBox()
LastNameBox.Name = "LastNameBox"
LastNameBox.Location = New Point(90, 10)
LastNameBox.Size = New Size(75, LastNameBox.Size.Height)
LastNameBox.CausesValidation = True
FlowLayout1.Controls.Add(LastNameBox)
ValidateButton = New Button()
ValidateButton.Text = "Validate"
ValidateButton.Location = New Point(170, 10)
ValidateButton.Size = New Size(75, ValidateButton.Size.Height)
FlowLayout1.Controls.Add(ValidateButton)
Me.Text = "Test Validation"
Me.Controls.Add(FlowLayout1)
End Sub
Private Sub FirstNameBox_Validating(ByVal sender As Object, ByVal e As System.ComponentModel.CancelEventArgs) Handles FirstNameBox.Validating
If FirstNameBox.Text.Length = 0 Then
e.Cancel = True
Else
e.Cancel = False
End If
End Sub
Private Sub LastNameBox_Validating(ByVal sender As Object, ByVal e As System.ComponentModel.CancelEventArgs) Handles LastNameBox.Validating
e.Cancel = False
End Sub
Private Sub ValidateButton_Click(ByVal sender As Object, ByVal e As EventArgs) Handles ValidateButton.Click
If ValidateChildren() Then
MessageBox.Show("Validation succeeded!")
Else
MessageBox.Show("Validation failed.")
End If
End Sub
End Class
Remarks
ValidateChildren will descend a control's hierarchy and examine each control to see if it supports validation. If the control can be selected by the user and its CausesValidation property is true
, ValidateChildren will cause the Validating event to occur. If any of the controls cancel the Validating event, this method will return false
; otherwise, it will return true
.
If a control is bound to a data source, and the Validating event occurs, it will cause the control to push its current data back to the data source.
Calling ValidateChildren is equivalent to calling ValidateChildren with a ValidationConstraints of None.
Applies to
ValidateChildren(ValidationConstraints)
Causes all of the child controls within a control that support validation to validate their data.
public:
virtual bool ValidateChildren(System::Windows::Forms::ValidationConstraints validationConstraints);
[System.ComponentModel.Browsable(false)]
public virtual bool ValidateChildren (System.Windows.Forms.ValidationConstraints validationConstraints);
[<System.ComponentModel.Browsable(false)>]
abstract member ValidateChildren : System.Windows.Forms.ValidationConstraints -> bool
override this.ValidateChildren : System.Windows.Forms.ValidationConstraints -> bool
Public Overridable Function ValidateChildren (validationConstraints As ValidationConstraints) As Boolean
Parameters
- validationConstraints
- ValidationConstraints
Places restrictions on which controls have their Validating event raised.
Returns
true
if all of the children validated successfully; otherwise, false
. If called from the Validating or Validated event handlers, this method will always return false
.
- Attributes
Examples
The following code example will only cause the Validating event to occur for immediate children of the form whose Enabled property is true
.
using System;
using System.Collections.Generic;
using System.Text;
using System.Drawing;
using System.Windows.Forms;
namespace ValidateChildrenWithConstraints
{
class Form1 : Form
{
public static void Main(string[] args)
{
Application.EnableVisualStyles();
Application.Run(new Form1());
}
private Form1()
{
this.Load += new EventHandler(Form1_Load);
}
void Form1_Load(object sender, EventArgs e)
{
// Create controls on form.
TextBox textBox1, textBox2, textBox3;
FlowLayoutPanel flowPanel1;
TextBox subTextBox1;
Button button1;
this.Size = new Size(500, 300);
this.AutoValidate = AutoValidate.Disable;
textBox1 = new TextBox();
textBox1.Location = new Point(20, 20);
textBox1.Size = new Size(75, textBox1.Size.Height);
textBox1.CausesValidation = true;
textBox1.Validating += new System.ComponentModel.CancelEventHandler(textBox1_Validating);
this.Controls.Add(textBox1);
textBox2 = new TextBox();
textBox2.Location = new Point(105, 20);
textBox2.Size = new Size(75, textBox2.Size.Height);
textBox2.CausesValidation = true;
textBox2.Validating += new System.ComponentModel.CancelEventHandler(textBox2_Validating);
this.Controls.Add(textBox2);
textBox3 = new TextBox();
textBox3.Location = new Point(190, 20);
textBox3.Size = new Size(75, textBox3.Size.Height);
textBox3.Enabled = false;
textBox3.CausesValidation = true;
textBox3.Validating += new System.ComponentModel.CancelEventHandler(textBox3_Validating);
this.Controls.Add(textBox3);
button1 = new Button();
button1.Text = "Click";
button1.Location = new Point(270, 20);
button1.Click += new EventHandler(button1_Click);
this.Controls.Add(button1);
flowPanel1 = new FlowLayoutPanel();
flowPanel1.Size = new Size(400, 100);
flowPanel1.Dock = DockStyle.Bottom;
subTextBox1 = new TextBox();
subTextBox1.CausesValidation = true;
subTextBox1.Validating += new System.ComponentModel.CancelEventHandler(subTextBox1_Validating);
flowPanel1.Controls.Add(subTextBox1);
this.Controls.Add(flowPanel1);
}
void subTextBox1_Validating(object sender, System.ComponentModel.CancelEventArgs e)
{
MessageBox.Show("subTextBox1 Validating!");
}
void textBox1_Validating(object sender, System.ComponentModel.CancelEventArgs e)
{
MessageBox.Show("textBox1 Validating!");
}
void textBox2_Validating(object sender, System.ComponentModel.CancelEventArgs e)
{
MessageBox.Show("textBox2 Validating!");
}
void textBox3_Validating(object sender, System.ComponentModel.CancelEventArgs e)
{
MessageBox.Show("textBox3 Validating!");
}
void button1_Click(object sender, EventArgs e)
{
this.ValidateChildren(ValidationConstraints.ImmediateChildren | ValidationConstraints.Enabled);
}
}
}
Imports System.Drawing
Imports System.Windows.Forms
Namespace ValidateChildrenWithConstraints
_
Class Form1
Inherits Form
Public Overloads Shared Sub Main(ByVal args() As String)
Application.EnableVisualStyles()
Application.Run(New Form1())
End Sub
Private Sub New()
AddHandler Me.Load, AddressOf Form1_Load
End Sub
Dim WithEvents TextBox1, TextBox2, TextBox3 As TextBox
Dim FlowPanel1 As FlowLayoutPanel
Dim WithEvents SubTextBox1 As TextBox
Dim WithEvents Button1 As Button
Sub Form1_Load(ByVal sender As Object, ByVal e As EventArgs)
' Create controls on form.
Me.Size = New Size(500, 300)
Me.AutoValidate = AutoValidate.Disable
TextBox1 = New TextBox()
TextBox1.Location = New Point(20, 20)
TextBox1.Size = New Size(75, TextBox1.Size.Height)
TextBox1.CausesValidation = True
Me.Controls.Add(TextBox1)
TextBox2 = New TextBox()
TextBox2.Location = New Point(105, 20)
TextBox2.Size = New Size(75, TextBox2.Size.Height)
TextBox2.CausesValidation = True
Me.Controls.Add(TextBox2)
TextBox3 = New TextBox()
TextBox3.Location = New Point(190, 20)
TextBox3.Size = New Size(75, TextBox3.Size.Height)
TextBox3.Enabled = False
TextBox3.CausesValidation = True
Me.Controls.Add(TextBox3)
Button1 = New Button()
Button1.Text = "Click"
Button1.Location = New Point(270, 20)
Me.Controls.Add(Button1)
FlowPanel1 = New FlowLayoutPanel()
FlowPanel1.Size = New Size(400, 100)
FlowPanel1.Dock = DockStyle.Bottom
SubTextBox1 = New TextBox()
SubTextBox1.CausesValidation = True
FlowPanel1.Controls.Add(SubTextBox1)
Me.Controls.Add(FlowPanel1)
End Sub
Sub SubTextBox1_Validating(ByVal sender As Object, ByVal e As System.ComponentModel.CancelEventArgs) Handles SubTextBox1.Validating
MessageBox.Show("SubTextBox1 Validating!")
End Sub
Sub TextBox1_Validating(ByVal sender As Object, ByVal e As System.ComponentModel.CancelEventArgs) Handles TextBox1.Validating
MessageBox.Show("TextBox1 Validating!")
End Sub
Sub TextBox2_Validating(ByVal sender As Object, ByVal e As System.ComponentModel.CancelEventArgs) Handles TextBox2.Validating
MessageBox.Show("TextBox2 Validating!")
End Sub
Sub TextBox3_Validating(ByVal sender As Object, ByVal e As System.ComponentModel.CancelEventArgs) Handles TextBox3.Validating
MessageBox.Show("TextBox3 Validating!")
End Sub
Sub Button1_Click(ByVal sender As Object, ByVal e As EventArgs) Handles button1.Click
Me.ValidateChildren((ValidationConstraints.ImmediateChildren Or ValidationConstraints.Enabled))
End Sub
End Class
End Namespace 'ValidateChildrenWithConstraints
Remarks
ValidateChildren will examine all the children of the current control, causing the Validating event to occur on a control if it meets the criteria spelled out by ValidationConstraints.
You may use several ValidationConstraints parameters at once by combining them with a bitwise OR operator. Combining parameters with a bitwise OR operator will result in a logical AND operation. For example, calling ValidateChildren(ValidationConstraints.ImmediateChildren | ValidationConstraints.Enabled)
will only raise the Validating event on controls that are both immediate children of the container AND are enabled.
Regardless of which parameters you specify for this method, a control must have its CausesValidation property set to true
in order for its Validating event to occur. You should also set the AutoValidate property of the control or of the control's container to false
if you want validation to happen only when you call ValidateChildren, and not when the user shifts focus from the control.
If a control is bound to a data source, and the Validating event occurs, it will cause the control to push its current data back to the data source.
You cannot achieve the opposite effect of a ValidationConstraints parameter by applying a bitwise negation operator. For example, if you supply the negative value of the Visible field to ValidateChildren, it will not validate all children that are not visible on the container. Supplying any negative parameter to ValidateChildren will have no effect on the container or its children.
Applies to
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