UpDownBase.ReadOnly Property

Gets or sets a value indicating whether the text can be changed by the use of the up or down buttons only.

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

public bool ReadOnly { get; set; }

Property Value

Type: System.Boolean
true if the text can be changed by the use of the up or down buttons only; otherwise, false. The default value is false.

By setting the ReadOnly property to true, you will eliminate the need for much validation of the Text property. The user will be restricted to the use of the up and down buttons to change the Text values. It will only allow them to select values you specify.

NoteNote

In the derived class DomainUpDown, the behavior described is slightly different. When ReadOnly is set to true and a key is pressed, the control selects the first item in the collection where the first character matches the key pressed.

The following code example uses the derived class NumericUpDown and sets some of its properties derived from UpDownBase. This code requires that you have a NumericUpDown control, two ComboBox controls, and three CheckBox controls created on a form. Label the ComboBox controls BorderStyle and TextAlign. Label the CheckBox controls InterceptArrowKeys, ReadOnly, and UpDownAlign. The code allows you to change the property values at run time and see how each affects the appearance and behavior of the spin box. Add the following items to the combo box labeled BorderStyle: None, Fixed3D, and FixedSingle. Add the following items to the combo box labeled TextAlign: Left, Right, and Center.

private void comboBox1_SelectedIndexChanged(Object sender, 
                                             EventArgs e)
 {
      // Set the BorderStyle property. 
     switch(comboBox1.Text)
     {
         case "Fixed3D":
             numericUpDown1.BorderStyle = System.Windows.Forms.BorderStyle.Fixed3D;
             break;
         case "None":
             numericUpDown1.BorderStyle = System.Windows.Forms.BorderStyle.None;
             break;
         case "FixedSingle":
             numericUpDown1.BorderStyle = System.Windows.Forms.BorderStyle.FixedSingle;
             break;
     }
 }

 private void comboBox2_SelectedIndexChanged(Object sender, 
                                             EventArgs e)
 {
      // Set the TextAlign property.     
     switch (comboBox2.Text)
     {
         case "Right":
             numericUpDown1.TextAlign = HorizontalAlignment.Right;
             break;
         case "Left":
             numericUpDown1.TextAlign = HorizontalAlignment.Left;
             break;
         case "Center":
             numericUpDown1.TextAlign = HorizontalAlignment.Center;
             break;
     }
 }

 private void checkBox1_Click(Object sender, 
                              EventArgs e)
 {
      // Evaluate and toggle the ReadOnly property. 
     if (numericUpDown1.ReadOnly)
     {
         numericUpDown1.ReadOnly = false;
     }
     else
     {
         numericUpDown1.ReadOnly = true;
     }
 }

 private void checkBox2_Click(Object sender, 
                              EventArgs e)
 {
      // Evaluate and toggle the InterceptArrowKeys property. 
     if (numericUpDown1.InterceptArrowKeys)
     {  
         numericUpDown1.InterceptArrowKeys = false;
     }
     else
     {
         numericUpDown1.InterceptArrowKeys = true;
     }
 }

 private void checkBox3_Click(Object sender, 
                              EventArgs e)
 {
      // Evaluate and toggle the UpDownAlign property. 
     if (numericUpDown1.UpDownAlign == LeftRightAlignment.Left)
     {
         numericUpDown1.UpDownAlign = LeftRightAlignment.Right;
     }
     else
     {
         numericUpDown1.UpDownAlign = LeftRightAlignment.Left;
     }
 }
 

.NET Framework

Supported in: 4.6, 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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