Question

I need to write a function in C# that would validated user entry for Payment Code in the form.

The form is used to collect information about payments. User can enter ad many rows/entries as he/she wishes by clicking "Add another Payment" button on the buttom. There is a Payment Code field that needs to be validates. It's a drop down list, with many values but the user is eligible to select only two of them: Meal and Travel. Every row/entry must have a Payment Code of either Meal or Travel, if user selects any other value or leaves this field blank an error message will be issued. Every form must have both Payment Values (Meal and Travel) and any combination. If user entered only Meal payment coded, but no Travel, an error message should specify that Payment information for Travel is missing. The same as if user would miss a Meal Code. The form looks like this:

Payment Code Payment Date Amount Currency Trave 08.01.2018 1765.54 USD Travel Meal Utility Medical Add another Payment

Just to summarize the requirements. C# code must validate Payment Code field in every row(entry), to make sure that nothing else but both Travel and Meal are selected, and issue a query (error) message if the field is blank, something other then Travel or Meal is selected or if either Travel or Meal is missing. The error message must specify whether Travel or Meal is missing.

Answer 1

Output will be like

Code will be like

using System;
using System.Windows.Forms;

namespace mEALtRAVELfORM
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();

comboBox1.Items.Add("Travel");
comboBox1.Items.Add("Meal");
comboBox1.Items.Add("Utility");
comboBox1.Items.Add("Medical");

comboBox2.Items.Add("Travel");
comboBox2.Items.Add("Meal");
comboBox2.Items.Add("Utility");
comboBox2.Items.Add("Medical");

}

private void button1_Click(object sender, EventArgs e)
{

  
if(comboBox1.Text !="Travel" && comboBox2.Text !="Travel" )

{
MessageBox.Show("Travel is missing");

}
else if (comboBox1.Text != "Meal" && comboBox2.Text != "Meal")
{

MessageBox.Show("Meal is missing");

}

else
{
MessageBox.Show("Successful");
}
  
}
}
}

Designer code will be like:

namespace mEALtRAVELfORM
{
partial class Form1
{
/// <summary>
/// Required designer variable.
/// </summary>
private System.ComponentModel.IContainer components = null;

/// <summary>
/// Clean up any resources being used.
/// </summary>
/// <param name="disposing">true if managed resources should be disposed; otherwise, false.</param>
protected override void Dispose(bool disposing)
{
if (disposing && (components != null))
{
components.Dispose();
}
base.Dispose(disposing);
}

#region Windows Form Designer generated code

/// <summary>
/// Required method for Designer support - do not modify
/// the contents of this method with the code editor.
/// </summary>
private void InitializeComponent()
{
this.comboBox1 = new System.Windows.Forms.ComboBox();
this.textBox1 = new System.Windows.Forms.TextBox();
this.button1 = new System.Windows.Forms.Button();
this.textBox2 = new System.Windows.Forms.TextBox();
this.comboBox2 = new System.Windows.Forms.ComboBox();
this.label1 = new System.Windows.Forms.Label();
this.label2 = new System.Windows.Forms.Label();
this.SuspendLayout();
//
// comboBox1
//
this.comboBox1.FormattingEnabled = true;
this.comboBox1.Location = new System.Drawing.Point(41, 41);
this.comboBox1.Name = "comboBox1";
this.comboBox1.Size = new System.Drawing.Size(121, 21);
this.comboBox1.TabIndex = 0;
//
// textBox1
//
this.textBox1.Location = new System.Drawing.Point(210, 42);
this.textBox1.Name = "textBox1";
this.textBox1.Size = new System.Drawing.Size(51, 20);
this.textBox1.TabIndex = 1;
//
// button1
//
this.button1.Location = new System.Drawing.Point(339, 42);
this.button1.Name = "button1";
this.button1.Size = new System.Drawing.Size(119, 100);
this.button1.TabIndex = 2;
this.button1.Text = "Add another Payment";
this.button1.UseVisualStyleBackColor = true;
this.button1.Click += new System.EventHandler(this.button1_Click);
//
// textBox2
//
this.textBox2.Location = new System.Drawing.Point(210, 118);
this.textBox2.Name = "textBox2";
this.textBox2.Size = new System.Drawing.Size(51, 20);
this.textBox2.TabIndex = 4;
//
// comboBox2
//
this.comboBox2.FormattingEnabled = true;
this.comboBox2.Location = new System.Drawing.Point(41, 117);
this.comboBox2.Name = "comboBox2";
this.comboBox2.Size = new System.Drawing.Size(121, 21);
this.comboBox2.TabIndex = 3;
//
// label1
//
this.label1.AutoSize = true;
this.label1.Location = new System.Drawing.Point(38, 9);
this.label1.Name = "label1";
this.label1.Size = new System.Drawing.Size(74, 13);
this.label1.TabIndex = 5;
this.label1.Text = "payment code";
//
// label2
//
this.label2.AutoSize = true;
this.label2.Location = new System.Drawing.Point(210, 9);
this.label2.Name = "label2";
this.label2.Size = new System.Drawing.Size(43, 13);
this.label2.TabIndex = 6;
this.label2.Text = "Amount";
//
// Form1
//
this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
this.ClientSize = new System.Drawing.Size(470, 365);
this.Controls.Add(this.label2);
this.Controls.Add(this.label1);
this.Controls.Add(this.textBox2);
this.Controls.Add(this.comboBox2);
this.Controls.Add(this.button1);
this.Controls.Add(this.textBox1);
this.Controls.Add(this.comboBox1);
this.Name = "Form1";
this.Text = "Form1";
this.ResumeLayout(false);
this.PerformLayout();

}

#endregion

private System.Windows.Forms.ComboBox comboBox1;
private System.Windows.Forms.TextBox textBox1;
private System.Windows.Forms.Button button1;
private System.Windows.Forms.TextBox textBox2;
private System.Windows.Forms.ComboBox comboBox2;
private System.Windows.Forms.Label label1;
private System.Windows.Forms.Label label2;
}
}

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