To print the selected item’s text from a ComboBox to a TextBox using the item’s index in C#:

1. First, create the ComboBox control on your form and add items to it. For example:

“`csharp
comboBox1.Items.Add(“Item 1”);
comboBox1.Items.Add(“Item 2”);
comboBox1.Items.Add(“Item 3”);
“`

2. Retrieve the index of the selected item from the ComboBox and perform the printing to the TextBox. You can use an event for this purpose. Here’s an example:

“`csharp
private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
{
int selectedIndex = comboBox1.SelectedIndex;

if (selectedIndex != -1)
{
// Retrieve the text of the selected item from the ComboBox and print it to the TextBox
string selectedText = comboBox1.Items[selectedIndex].ToString();
textBox1.Text = selectedText;
}
}
“`

In the above code, we use the ComboBox’s `SelectedIndexChanged` event to get the index of the selected item from the ComboBox. Then, we use that index to retrieve the text of the selected item and display it in a TextBox.

This way, you can print the selected item’s text from a ComboBox to a TextBox.