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# Preface

In this chapter we want  to Calculate Body Mass Index (BMI).

# Process

The following steps show how Calculate Body Mass Index (BMI):

1. First, Click New Project in Start Page or On File Menu.
2. In New Project Dialog , Click Windows On Left Pane And Windows Forms Application On Middle Pane.
3. Change form layout to this Mode:

4.Add these Items To ComboBox :

• 19 to 24
• 25 to 34
• 35 to 44
• 45 to 54
• 55 to 64
• More Than 65

5.Set BMI Textbox Enable To False.

6.We Know The BMI  Is Mass(Kg) / (height(m))2.Then Into Click Event Of Calculate Your BMI Button Write This Code :

`double` `bmi;`
` ``double` `vazn = ``double``.Parse(numericUpDown2.Value.ToString());`
` ``double` `ghad2 = Math.Pow(``double``.Parse(numericUpDown1.Value.ToString()), 2);`
` ``bmi = vazn / ghad2;`
` ``if` `(bmi.ToString().Length > 5)`
` ``{`
` ``textBox1.Text = (vazn / ghad2).ToString().Remove(5);`
` ``}`
` ``else`
` ``{`
` ``textBox1.Text = (vazn / ghad2).ToString();`
` ``}`
` ``if` `(bmi < 16.5 && bmi > 11)`
` ``{`
` ````label15.Visible = ````true``;`
` ````label16.Visible = ````false``;`
` ````label17.Visible = ````false``;`
` ````label18.Visible = ````false``;`
` ````label19.Visible = ````false``;`
` ``}`

` ``else` `if` ``` (bmi < 18.5 && bmi > 16.5)```
` ``{`
` ````label15.Visible = ````false``;`
` ````label16.Visible = ````true``;`
` ````label17.Visible = ````false``;`
` ````label18.Visible = ````false``;`
` ````label19.Visible = ````false``;`
` ``}`
` ``else` `if` ``` (bmi < 25 && bmi > 18.5)```
` ``{`
` ````label15.Visible = ````false``;`
` ````label16.Visible = ````false``;`
` ````label17.Visible = ````true``;`
` ````label18.Visible = ````false``;`
` ````label19.Visible = ````false``;`
` ``}`
` ``else` `if` ``` (bmi < 30 && bmi > 25)```
` ``{`
` ````label15.Visible = ````false``;`
` ````label16.Visible = ````false``;`
` ````label17.Visible = ````false``;`
` ````label18.Visible = ````true``;`
` ````label19.Visible = ````false``;`
` ``}`
` ``else` `if` ``` (bmi > 30)```
` ``{`
` ````label15.Visible = ````false``;`
` ````label16.Visible = ````false``;`
` ````label17.Visible = ````false``;`
` ````label18.Visible = ````true``;`
` ````label19.Visible = ````false``;`
` ``}`

7.For Show Appropriate BMI , Into The SelectedIndexChanged Event Of Age Range ComboBox , Write This Code :

`if` `(comboBox1.SelectedIndex == 0)`
` ``{`
` ````label14.Text = ````"22"``;`
` ``}`
` ``else` `if` ``` (comboBox1.SelectedIndex == 1)```
` ``{`
` ````label14.Text = ````"23"``;`
` ``}`
` ``else` `if` ``` (comboBox1.SelectedIndex == 2)```
` ``{`
` ````label14.Text = ````"24"``;`
` ``}`
` ``else` `if` ``` (comboBox1.SelectedIndex == 3)```
` ``{`
` ````label14.Text = ````"25"``;`
` ``}`
` ``else` `if` ``` (comboBox1.SelectedIndex == 4)```
` ``{`
` ````label14.Text = ````"26"``;`
` ``}`
` ``else` `if` ``` (comboBox1.SelectedIndex == 5)```
` ``{`
` ````label14.Text = ````"27"``;`
` ``}`