SelectAll method in custom TextBox (Winforms .NET 7)

Question

I have made a Custom TextBox that is a panel with a TextBox inside.

What i'm trying to do is [CustomTextBox name].SelectAll(); where it returns [TextBox nameInsideCustomControl].SelectAll();

[...] is just a name.

How can i implement it?

I have tried:

[Category("Custom")]
public void SelectAll
{
    get { textBox1.SelectAll(); }
}

But i don't think it's right.

Answer: public void SelectAll() => textBox1.SelectAll();. It's a method, not a property. – dr.null

Answer 1

You have a CustomTextBox that inherits from Panel and you want to be able to select all text in the TextBox that it contains.

To achieve this objective, first make sure that your CustomTextBox exposes a pubic method named SelectAll that forwards the command to the private TextBox it contains. But in addition to that you will either need to make sure that the internal TextBox receives focus or set the HideSelection property of the internal TextBox to false. Otherwise you may still not see the selection highlighted.

---

Custom Text Box example

public partial class CustomTextBox : Panel
{
    public void SelectAll()
    {
        textBox1.SelectAll();
        // Ensure text box gets the focus.
        textBox1.Focus();
    }
    public void LoadTestData() => 
        textBox1.Text = "Don't forget to give Focus to the TextBox!";
    public CustomTextBox()
    {
        BackColor= Color.Azure;
        label1 = new System.Windows.Forms.Label();
        textBox1 = new System.Windows.Forms.TextBox();

        #region I N I T I A L I Z E
        SuspendLayout();

        label1.AutoSize = true;
        label1.Location = new System.Drawing.Point(12, 17);
        label1.Size = new System.Drawing.Size(143, 25);
        label1.TabIndex = 0;
        label1.Text = "Custom Text Box";

        textBox1.Anchor = ((System.Windows.Forms.AnchorStyles)((((System.Windows.Forms.AnchorStyles.Top | System.Windows.Forms.AnchorStyles.Bottom)
        | System.Windows.Forms.AnchorStyles.Left)
        | System.Windows.Forms.AnchorStyles.Right)));
        textBox1.Location = new System.Drawing.Point(190, 17);
        textBox1.Multiline = true;
        textBox1.Size = new System.Drawing.Size(206, 126);
        textBox1.TabIndex = 1;
        textBox1.HideSelection = false;

        Controls.Add(textBox1);
        Controls.Add(label1);
        Name = "CustomTextBox";
        Size = new System.Drawing.Size(424, 157);
        ResumeLayout(false);
        PerformLayout();
        #endregion I N I T I A L I Z E
    }
    private Label label1;
    private TextBox textBox1;
}

---

Minimal Test Code

public partial class MainForm : Form
{
    public MainForm()
    {
        InitializeComponent();
        customTextBoxPanel.LoadTestData();
        buttonSelectAllTest.Click += onClickSelectAllTest;
    }

    private void onClickSelectAllTest(object? sender, EventArgs e)
    {
        customTextBoxPanel.SelectAll();
    }
}