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ComboBox.FindStringExact Method (String)

Finds the first item in the combo box that matches the specified string.

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

public int FindStringExact(
	string s
)

Parameters

s
Type: System.String

The String to search for.

Return Value

Type: System.Int32
The zero-based index of the first item found; returns -1 if no match is found, or 0 if the s parameter specifies Empty.

The search performed by this method is not case-sensitive. The s parameter is a string to compare against the text associated with the items in the combo box list. The search looks for a match starting from the beginning of the text, returning the first item in the list that matches the specified substring. You can then perform tasks, such as removing the item that contains the search text using the Remove method or changing the item's text. Once you have found the specified text, if you want to search for other instances of the text in the ComboBox, you must use the version of the FindStringExact method that provides a parameter for specifying a starting index within the ComboBox. If you want to perform partial word search instead of an exact word match, use the FindString method.

The following code example demonstrates how to initialize a ComboBox control by setting the MaxDropDownItems and DropDownStyle properties and using the FindStringExact methods to search the ComboBox. It also shows handling the SelectedIndexChanged event.

using System.Windows.Forms;

public class Form1:
	System.Windows.Forms.Form

{
	public Form1() : base()
	{        
		InitializeComboBox();
		InitializeTextBox();
		this.Label1 = new System.Windows.Forms.Label();
		this.SuspendLayout();
		this.Label1.Location = new System.Drawing.Point(8, 24);
		this.Label1.Name = "Label1";
		this.Label1.Size = new System.Drawing.Size(120, 32);
		this.Label1.TabIndex = 1;
		this.Label1.Text = "Use drop-down to choose a name:";
		this.Label1.TextAlign = System.Drawing.ContentAlignment.MiddleRight;
		this.ClientSize = new System.Drawing.Size(292, 266);
		this.Controls.Add(this.Label1);
		this.Name = "Form1";
		this.Text = "Form1";
		this.ResumeLayout(false);
	}

	public static void Main()
	{
		Application.Run(new Form1());
	}


	internal System.Windows.Forms.Label Label1;




	// Declare and initialize the text box. 
	// This text box text will be update programmatically. The user is not  
	// allowed to update it, so the ReadOnly property is set to true. 
	internal System.Windows.Forms.TextBox TextBox1;

	private void InitializeTextBox()
	{
		this.TextBox1 = new System.Windows.Forms.TextBox();
		this.TextBox1.ScrollBars = ScrollBars.Vertical;
		this.TextBox1.Location = new System.Drawing.Point(64, 128);
		this.TextBox1.Multiline = true;
		this.TextBox1.Name = "TextBox1";
		this.TextBox1.ReadOnly = true;
		this.TextBox1.Size = new System.Drawing.Size(184, 120);
		this.TextBox1.TabIndex = 4;
		this.TextBox1.Text = "Employee and Number of Awards:";
		this.Controls.Add(this.TextBox1);
	}

	// Declare comboBox1 as a ComboBox. 
	internal System.Windows.Forms.ComboBox ComboBox1;

	// This method initializes the combo box, adding a large string array 
	// but limiting the drop-down size to six rows so the combo box doesn't  
	// cover other controls when it expands. 
	private void InitializeComboBox()
	{
		this.ComboBox1 = new System.Windows.Forms.ComboBox();
		string[] employees = new string[]{"Hamilton, David", "Hensien, Kari",
				"Hammond, Maria", "Harris, Keith", "Henshaw, Jeff D.", 
				"Hanson, Mark", "Harnpadoungsataya, Sariya", 
				"Harrington, Mark", "Harris, Keith", "Hartwig, Doris", 
				"Harui, Roger", "Hassall, Mark", "Hasselberg, Jonas", 
				"Harnpadoungsataya, Sariya", "Henshaw, Jeff D.", 
				"Henshaw, Jeff D.", "Hensien, Kari", "Harris, Keith", 
				"Henshaw, Jeff D.", "Hensien, Kari", "Hasselberg, Jonas",
				"Harrington, Mark", "Hedlund, Magnus", "Hay, Jeff", 
				"Heidepriem, Brandon D."};

		ComboBox1.Items.AddRange(employees);
		this.ComboBox1.Location = new System.Drawing.Point(136, 32);
        this.ComboBox1.IntegralHeight = false;
        this.ComboBox1.MaxDropDownItems = 5;
		this.ComboBox1.DropDownStyle = ComboBoxStyle.DropDownList;
		this.ComboBox1.Name = "ComboBox1";
		this.ComboBox1.Size = new System.Drawing.Size(136, 81);
		this.ComboBox1.TabIndex = 0;
		this.Controls.Add(this.ComboBox1);
		
		// Associate the event-handling method with the  
		// SelectedIndexChanged event. 
		this.ComboBox1.SelectedIndexChanged += 
			new System.EventHandler(ComboBox1_SelectedIndexChanged);
	}

	// This method is called when the user changes his or her selection. 
	// It searches for all occurrences of the selected employee's 
	// name in the Items array and adds the employee's name and  
	// the number of occurrences to TextBox1.Text. 

	// CAUTION   This code exposes a known bug: If the index passed to the  
	// FindStringExact(searchString, index) method is the last index  
	// of the array, the code throws an exception. 
	private void ComboBox1_SelectedIndexChanged(object sender, 
		System.EventArgs e)
	{

		ComboBox comboBox = (ComboBox) sender;

		// Save the selected employee's name, because we will remove 
		// the employee's name from the list. 
		string selectedEmployee = (string) ComboBox1.SelectedItem;

		int count = 0;
		int resultIndex = -1;

		// Call the FindStringExact method to find the first  
		// occurrence in the list.
		resultIndex = ComboBox1.FindStringExact(selectedEmployee);

		// Remove the name as it is found, and increment the found count.  
		// Then call the FindStringExact method again, passing in the  
		// index of the current found item so the search starts there  
		// instead of at the beginning of the list. 
		while (resultIndex!=-1)
		{
			ComboBox1.Items.RemoveAt(resultIndex);
			count += 1;
			resultIndex = ComboBox1.FindStringExact(selectedEmployee, 
				resultIndex);
		}
		// Update the text in Textbox1.
		TextBox1.Text = TextBox1.Text+ "\r\n" + selectedEmployee + ": "
			+ count;
	}

}

.NET Framework

Supported in: 4.5.2, 4.5.1, 4.5, 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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