ErrorProvider Class
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ErrorProvider Class


Provides a user interface for indicating that a control on a form has an error associated with it.

Namespace:   System.Windows.Forms
Assembly:  System.Windows.Forms (in System.Windows.Forms.dll)


[ComplexBindingPropertiesAttribute("DataSource", "DataMember")]
public class ErrorProvider : Component, IExtenderProvider, ISupportInitialize


Initializes a new instance of the ErrorProvider class and initializes the default settings for BlinkRate, BlinkStyle, and the Icon.


Initializes a new instance of the ErrorProvider class attached to a container.


Initializes a new instance of the ErrorProvider class attached to an IContainer implementation.


Gets or sets the rate at which the error icon flashes.


Gets or sets a value indicating when the error icon flashes.


Gets a value indicating whether the component can raise an event.(Inherited from Component.)


Gets the IContainer that contains the Component.(Inherited from Component.)


Gets or sets a value indicating the parent control for this ErrorProvider.


Gets or sets the list within a data source to monitor.


Gets or sets the data source that the ErrorProvider monitors.


Gets a value that indicates whether the Component is currently in design mode.(Inherited from Component.)


Gets the list of event handlers that are attached to this Component.(Inherited from Component.)


Gets or sets the Icon that is displayed next to a control when an error description string has been set for the control.


Gets or sets a value that indicates whether the component is used in a locale that supports right-to-left fonts.


Gets or sets the ISite of the Component.(Overrides Component.Site.)


Gets or sets an object that contains data about the component.

System_CAPS_pubmethodBindToDataAndErrors(Object, String)

Provides a method to set both the DataSource and DataMember at run time.


Gets a value indicating whether a control can be extended.


Clears all settings associated with this component.


Creates an object that contains all the relevant information required to generate a proxy used to communicate with a remote object.(Inherited from MarshalByRefObject.)


Releases all resources used by the Component.(Inherited from Component.)


Releases the unmanaged resources used by the Component and optionally releases the managed resources.(Overrides Component.Dispose(Boolean).)


Determines whether the specified object is equal to the current object.(Inherited from Object.)


Releases unmanaged resources and performs other cleanup operations before the Component is reclaimed by garbage collection.(Inherited from Component.)


Returns the current error description string for the specified control.


Serves as the default hash function. (Inherited from Object.)


Gets a value indicating where the error icon should be placed in relation to the control.


Returns the amount of extra space to leave next to the error icon.


Retrieves the current lifetime service object that controls the lifetime policy for this instance.(Inherited from MarshalByRefObject.)


Returns an object that represents a service provided by the Component or by its Container.(Inherited from Component.)


Gets the Type of the current instance.(Inherited from Object.)


Obtains a lifetime service object to control the lifetime policy for this instance.(Inherited from MarshalByRefObject.)


Creates a shallow copy of the current Object.(Inherited from Object.)


Creates a shallow copy of the current MarshalByRefObject object.(Inherited from MarshalByRefObject.)


Raises the RightToLeftChanged event.

System_CAPS_pubmethodSetError(Control, String)

Sets the error description string for the specified control.

System_CAPS_pubmethodSetIconAlignment(Control, ErrorIconAlignment)

Sets the location where the error icon should be placed in relation to the control.

System_CAPS_pubmethodSetIconPadding(Control, Int32)

Sets the amount of extra space to leave between the specified control and the error icon.


Returns a String containing the name of the Component, if any. This method should not be overridden.(Inherited from Component.)


Provides a method to update the bindings of the DataSource, DataMember, and the error text.


Occurs when the component is disposed by a call to the Dispose method. (Inherited from Component.)


Occurs when the RightToLeft property changes value.


Signals the object that initialization is starting.


Signals the object that initialization is complete.

ErrorProvider presents a simple mechanism for indicating to the end user that a control on a form has an error associated with it. If an error description string is specified for the control, an icon appears next to the control. The icon flashes in the manner specified by BlinkStyle, at the rate specified by BlinkRate. When the mouse hovers over the icon, a ToolTip appears showing the error description string.

Typically, you use ErrorProvider in association with data-bound controls. When using ErrorProvider with data-bound controls, you must specify the ContainerControl, either in the constructor or by setting the ContainerControl property.


The ErrorProvider component does not provide built-in support for accessibility clients. To make your application accessible when using this component, you must provide an additional, accessible feedback mechanism.

The following code example demonstrates using the ErrorProvider class to notify the user of a data entry error. The example creates a Form that contains a TextBox control, a NumericUpDown control, and a ComboBox control, each validating its content, and an ErrorProvider for each control. The example sets error icon options using the BlinkRate and BlinkStyle properties and the SetIconAlignment and SetIconPadding methods. The SetError method is called with or without appropriate error text during a control’s Validated event, depending upon the content in the control.

using System;
using System.Drawing;
using System.Windows.Forms;

namespace ErrorProvider
    public class Form1 : System.Windows.Forms.Form
        private System.Windows.Forms.Label label1;
        private System.Windows.Forms.Label label2;
        private System.Windows.Forms.Label label4;
        private System.Windows.Forms.Label label5;
        private System.Windows.Forms.Label label6;
        private System.Windows.Forms.Label label3;
        private System.Windows.Forms.TextBox nameTextBox1;
        private System.Windows.Forms.NumericUpDown ageUpDownPicker;
        private System.Windows.Forms.ComboBox favoriteColorComboBox;
        private System.Windows.Forms.ErrorProvider ageErrorProvider;
        private System.Windows.Forms.ErrorProvider nameErrorProvider;
        private System.Windows.Forms.ErrorProvider favoriteColorErrorProvider;

        static void Main() 
            Application.Run(new Form1());

        public Form1()
            this.nameTextBox1 = new System.Windows.Forms.TextBox();
            this.label1 = new System.Windows.Forms.Label();
            this.label2 = new System.Windows.Forms.Label();
            this.ageUpDownPicker = new System.Windows.Forms.NumericUpDown();
            this.favoriteColorComboBox = new System.Windows.Forms.ComboBox();
            this.label3 = new System.Windows.Forms.Label();
            this.label4 = new System.Windows.Forms.Label();
            this.label5 = new System.Windows.Forms.Label();
            this.label6 = new System.Windows.Forms.Label();

            // Name Label
            this.label1.Location = new System.Drawing.Point(56, 32);
            this.label1.Size = new System.Drawing.Size(40, 23);
            this.label1.Text = "Name:";

            // Age Label
            this.label2.Location = new System.Drawing.Point(40, 64);
            this.label2.Size = new System.Drawing.Size(56, 23);
            this.label2.Text = "Age (3-5)";           

            // Favorite Color Label
            this.label3.Location = new System.Drawing.Point(24, 96);
            this.label3.Size = new System.Drawing.Size(80, 24);
            this.label3.Text = "Favorite color";

            // ErrorBlinkStyle.AlwaysBlink Label
            this.label4.Location = new System.Drawing.Point(264, 32);
            this.label4.Size = new System.Drawing.Size(160, 23);
            this.label4.Text = "ErrorBlinkStyle.AlwaysBlink";

            // ErrorBlinkStyle.BlinkIfDifferentError Label
            this.label5.Location = new System.Drawing.Point(264, 64);
            this.label5.Size = new System.Drawing.Size(200, 23);
            this.label5.Text = "ErrorBlinkStyle.BlinkIfDifferentError";

            // ErrorBlinkStyle.NeverBlink Label
            this.label6.Location = new System.Drawing.Point(264, 96);
            this.label6.Size = new System.Drawing.Size(200, 23);
            this.label6.Text = "ErrorBlinkStyle.NeverBlink";

            // Name TextBox
            this.nameTextBox1.Location = new System.Drawing.Point(112, 32);
            this.nameTextBox1.Size = new System.Drawing.Size(120, 20);
            this.nameTextBox1.TabIndex = 0;
            this.nameTextBox1.Validated += new System.EventHandler(this.nameTextBox1_Validated);

            // Age NumericUpDown
            this.ageUpDownPicker.Location = new System.Drawing.Point(112, 64);
            this.ageUpDownPicker.Maximum = new System.Decimal(new int[] {150,0,0,0});
            this.ageUpDownPicker.TabIndex = 4;
            this.ageUpDownPicker.Validated += new System.EventHandler(this.ageUpDownPicker_Validated);

            // Favorite Color ComboBox
            this.favoriteColorComboBox.Items.AddRange(new object[] {"None","Red","Yellow",
            this.favoriteColorComboBox.Location = new System.Drawing.Point(112, 96);
            this.favoriteColorComboBox.Size = new System.Drawing.Size(120, 21);
            this.favoriteColorComboBox.TabIndex = 5;
            this.favoriteColorComboBox.Validated += new System.EventHandler(this.favoriteColorComboBox_Validated);

            // Set up how the form should be displayed and add the controls to the form.
            this.ClientSize = new System.Drawing.Size(464, 150);
            this.Controls.AddRange(new System.Windows.Forms.Control[] {
            this.Text = "Error Provider Example";

            // Create and set the ErrorProvider for each data entry control.

            nameErrorProvider = new  System.Windows.Forms.ErrorProvider();
            nameErrorProvider.SetIconAlignment (this.nameTextBox1, ErrorIconAlignment.MiddleRight);
            nameErrorProvider.SetIconPadding (this.nameTextBox1, 2);
            nameErrorProvider.BlinkRate = 1000;
            nameErrorProvider.BlinkStyle = System.Windows.Forms.ErrorBlinkStyle.AlwaysBlink;

            ageErrorProvider = new  System.Windows.Forms.ErrorProvider();
            ageErrorProvider.SetIconAlignment (this.ageUpDownPicker, ErrorIconAlignment.MiddleRight);
            ageErrorProvider.SetIconPadding (this.ageUpDownPicker, 2);
            ageErrorProvider.BlinkStyle = System.Windows.Forms.ErrorBlinkStyle.BlinkIfDifferentError;

            favoriteColorErrorProvider = new  System.Windows.Forms.ErrorProvider();
            favoriteColorErrorProvider.SetIconAlignment (this.favoriteColorComboBox, ErrorIconAlignment.MiddleRight);
            favoriteColorErrorProvider.SetIconPadding (this.favoriteColorComboBox, 2);
            favoriteColorErrorProvider.BlinkRate = 1000;
            favoriteColorErrorProvider.BlinkStyle = System.Windows.Forms.ErrorBlinkStyle.NeverBlink;

        private void nameTextBox1_Validated(object sender, System.EventArgs e)
                // Clear the error, if any, in the error provider.
                nameErrorProvider.SetError(this.nameTextBox1, String.Empty);
                // Set the error if the name is not valid.
                nameErrorProvider.SetError(this.nameTextBox1, "Name is required.");

        private void ageUpDownPicker_Validated(object sender, System.EventArgs e)
            if (IsAgeTooYoung())
                // Set the error if the age is too young.
                ageErrorProvider.SetError(this.ageUpDownPicker, "Age not old enough");
            else if (IsAgeTooOld())
                // Set the error if the age is too old.
                ageErrorProvider.SetError(this.ageUpDownPicker, "Age is too old");
                // Clear the error, if any, in the error provider.
                ageErrorProvider.SetError(this.ageUpDownPicker, String.Empty);

        private void favoriteColorComboBox_Validated(object sender, System.EventArgs e) 
            if (!IsColorValid())
                // Set the error if the favorite color is not valid.
                favoriteColorErrorProvider.SetError(this.favoriteColorComboBox, "Must select a color.");
                // Clear the error, if any, in the error provider.
                favoriteColorErrorProvider.SetError(this.favoriteColorComboBox, String.Empty);

        // Functions to verify data.
        private bool IsNameValid() 
            // Determine whether the text box contains a zero-length string.
            return (nameTextBox1.Text.Length > 0);

        private bool IsAgeTooYoung() 
            // Determine whether the age value is less than three.
            return (ageUpDownPicker.Value < 3);

        private bool IsAgeTooOld() 
            // Determine whether the age value is greater than five.
            return (ageUpDownPicker.Value > 5 );

        private bool IsColorValid() 
            // Determine whether the favorite color has a valid value.
            return ((favoriteColorComboBox.SelectedItem != null) &&

The following code example shows how to use the ErrorProvider with a DataSource and DataMember to indicate a data error to the user.

private void InitializeComponent()
     // Standard control setup.
     // You set the DataSource to a data set, and the DataMember to a table.
     errorProvider1.DataSource = dataSet1 ;
     errorProvider1.DataMember = dataTable1.TableName ;
     errorProvider1.ContainerControl = this ;
     errorProvider1.BlinkRate = 200 ;
     // Since the ErrorProvider control does not have a visible component,
     // it does not need to be added to the form. 

 private void buttonSave_Click(object sender, System.EventArgs e)
     // Checks for a bad post code.
     DataTable CustomersTable;
     CustomersTable = dataSet1.Tables["Customers"];
     foreach (DataRow row in (CustomersTable.Rows)) 
         if (Convert.ToBoolean(row["PostalCodeIsNull"])) 
             row.RowError="The Customer details contain errors";
             row.SetColumnError("PostalCode", "Postal Code required");

.NET Framework
Available since 1.1

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

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