ErrorProvider.SetError : ErrorProvider « System.Windows.Forms « C# / C Sharp by API

1. C# / C Sharp by API
2. System.Windows.Forms
3. ErrorProvider

ErrorProvider.SetError

  
using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;

public class ErrorForm : System.Windows.Forms.Form
{
  private System.ComponentModel.Container components = null;
  private System.Windows.Forms.Label label1;
  private System.Windows.Forms.Button btnValidate;
  private System.Windows.Forms.ErrorProvider errorProvider1;
  private System.Windows.Forms.TextBox txtInput;

  public ErrorForm()
  {
    InitializeComponent();
  }

  protected override void Dispose( bool disposing )
  {
    if( disposing )
    {
      if (components != null) 
      {
        components.Dispose();
      }
    }
    base.Dispose( disposing );
  }

  private void InitializeComponent()
  {
    this.errorProvider1 = new System.Windows.Forms.ErrorProvider();
    this.label1 = new System.Windows.Forms.Label();
    this.txtInput = new System.Windows.Forms.TextBox();
    this.btnValidate = new System.Windows.Forms.Button();
    this.SuspendLayout();
    // 
    // errorProvider1
    // 
    this.errorProvider1.BlinkRate = 500;
    this.errorProvider1.BlinkStyle = System.Windows.Forms.ErrorBlinkStyle.AlwaysBlink;
    this.errorProvider1.ContainerControl = this;
    // 
    // label1
    // 
    this.label1.Font = new System.Drawing.Font("Arial Black", 12F);
    this.label1.Location = new System.Drawing.Point(8, 8);
    this.label1.Name = "label1";
    this.label1.Size = new System.Drawing.Size(376, 56);
    this.label1.TabIndex = 2;
    this.label1.Text = "The following text box only allows 5 characters.  Try to enter more...";
    // 
    // txtInput
    // 
    this.txtInput.Location = new System.Drawing.Point(144, 80);
    this.txtInput.Name = "txtInput";
    this.txtInput.Size = new System.Drawing.Size(120, 20);
    this.txtInput.TabIndex = 0;
    this.txtInput.Text = "";
    this.txtInput.Validating += new System.ComponentModel.CancelEventHandler(this.txtInput_Validating);
    // 
    // btnValidate
    // 
    this.btnValidate.Location = new System.Drawing.Point(16, 72);
    this.btnValidate.Name = "btnValidate";
    this.btnValidate.Size = new System.Drawing.Size(112, 32);
    this.btnValidate.TabIndex = 1;
    this.btnValidate.Text = "OK";
    // 
    // ErrorForm
    // 
    this.AutoScaleBaseSize = new System.Drawing.Size(5, 13);
    this.ClientSize = new System.Drawing.Size(400, 125);
    this.Controls.Add(this.label1);
    this.Controls.Add(this.btnValidate);
    this.Controls.Add(this.txtInput);
    this.Name = "ErrorForm";
    this.Text = "Error Trapper";
    this.ResumeLayout(false);

  }

  [STAThread]
  static void Main() 
  {
    Application.Run(new ErrorForm());
  }

  private void txtInput_Validating(object sender, System.ComponentModel.CancelEventArgs e)
  {
    // Check if the text length is greater than 5.
    if(txtInput.Text.Length > 5)
    {
      errorProvider1.SetError( txtInput, "Can't be greater than 5!");
    } 
    else
      errorProvider1.SetError(txtInput, "");
  }
}

   
    
  

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