如果背景已更改，则文本框不使用可读的颜色

Question

看来，当您设置文本框的后面色时，从那时起，Readonly就停止影响背色。我有用户控制，装饰引擎在哪里跟踪验证，并在验证该值后突出显示文本框的某些颜色。但是，一旦我分配了color.yellow或systemcolors.window到textbox.backcolor，sette textbox.readonly什么都不做。

这非常容易复制：

        public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }



        private void button1_Click(object sender, EventArgs e)
        {
            textBox1.ReadOnly = !textBox1.ReadOnly;
        }


        private void button2_Click(object sender, EventArgs e)
        {
            textBox2.ReadOnly = !textBox2.ReadOnly;
        }

        private void button3_Click(object sender, EventArgs e)
        {
            textBox2.BackColor = Color.Blue;
        }

        private void textBox1_ReadOnlyChanged(object sender, EventArgs e)
        {
            label1.Text = $"Readonly: {textBox1.ReadOnly}{Environment.NewLine}Color: {textBox1.BackColor}";
        }

        private void textBox2_ReadOnlyChanged(object sender, EventArgs e)
        {
            label2.Text = $"Readonly: {textBox2.ReadOnly}{Environment.NewLine}Color: {textBox2.BackColor}";
        }

        private void InitializeComponent()
        {
            this.button1 = new System.Windows.Forms.Button();
            this.button2 = new System.Windows.Forms.Button();
            this.button3 = new System.Windows.Forms.Button();
            this.textBox1 = new System.Windows.Forms.TextBox();
            this.textBox2 = new System.Windows.Forms.TextBox();
            this.label1 = new System.Windows.Forms.Label();
            this.label2 = new System.Windows.Forms.Label();
            this.SuspendLayout();
            // 
            // button1
            // 
            this.button1.Location = new System.Drawing.Point(138, 286);
            this.button1.Name = "button1";
            this.button1.Size = new System.Drawing.Size(75, 23);
            this.button1.TabIndex = 1;
            this.button1.Text = "button1";
            this.button1.UseVisualStyleBackColor = true;
            this.button1.Click += new System.EventHandler(this.button1_Click);
            // 
            // button2
            // 
            this.button2.Location = new System.Drawing.Point(219, 286);
            this.button2.Name = "button2";
            this.button2.Size = new System.Drawing.Size(75, 23);
            this.button2.TabIndex = 3;
            this.button2.Text = "button2";
            this.button2.UseVisualStyleBackColor = true;
            this.button2.Click += new System.EventHandler(this.button2_Click);
            // 
            // button3
            // 
            this.button3.Location = new System.Drawing.Point(300, 286);
            this.button3.Name = "button3";
            this.button3.Size = new System.Drawing.Size(75, 23);
            this.button3.TabIndex = 4;
            this.button3.Text = "button3";
            this.button3.UseVisualStyleBackColor = true;
            this.button3.Click += new System.EventHandler(this.button3_Click);
            // 
            // textBox1
            // 
            this.textBox1.Location = new System.Drawing.Point(108, 190);
            this.textBox1.Name = "textBox1";
            this.textBox1.Size = new System.Drawing.Size(100, 22);
            this.textBox1.TabIndex = 5;
            this.textBox1.ReadOnlyChanged += new System.EventHandler(this.textBox1_ReadOnlyChanged);
            // 
            // textBox2
            // 
            this.textBox2.Location = new System.Drawing.Point(308, 190);
            this.textBox2.Name = "textBox2";
            this.textBox2.Size = new System.Drawing.Size(100, 22);
            this.textBox2.TabIndex = 6;
            this.textBox2.ReadOnlyChanged += new System.EventHandler(this.textBox2_ReadOnlyChanged);
            // 
            // label1
            // 
            this.label1.AutoSize = true;
            this.label1.Location = new System.Drawing.Point(105, 215);
            this.label1.Name = "label1";
            this.label1.Size = new System.Drawing.Size(76, 17);
            this.label1.TabIndex = 7;
            this.label1.Text = "Readonly: ";
            // 
            // label2
            // 
            this.label2.AutoSize = true;
            this.label2.Location = new System.Drawing.Point(305, 215);
            this.label2.Name = "label2";
            this.label2.Size = new System.Drawing.Size(72, 17);
            this.label2.TabIndex = 8;
            this.label2.Text = "Readonly:";
            // 
            // Form1
            // 
            this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.None;
            this.ClientSize = new System.Drawing.Size(800, 450);
            this.Controls.Add(this.label2);
            this.Controls.Add(this.label1);
            this.Controls.Add(this.textBox2);
            this.Controls.Add(this.textBox1);
            this.Controls.Add(this.button3);
            this.Controls.Add(this.button2);
            this.Controls.Add(this.button1);
            this.Name = "Form1";
            this.Text = "Form1";
            this.ResumeLayout(false);
            this.PerformLayout();

        }

#endregion
        private System.Windows.Forms.Button button1;
        private System.Windows.Forms.Button button2;
        private System.Windows.Forms.Button button3;
        private System.Windows.Forms.TextBox textBox1;
        private System.Windows.Forms.TextBox textBox2;
        private System.Windows.Forms.Label label1;
        private System.Windows.Forms.Label label2;
    }

只需运行该表单，重复单击按钮1和按钮2，并且两个文本框都会从默认窗口循环到随着ReadOnly属性的变化，从默认窗口循环到控制背景颜色。 Button 3，将TextBox2的背色设置为蓝色，从那时起，单击Button2对后彩没有影响。

我不想要这种行为。我想影响背色，但我希望读取我分配的任何自定义背色。

我该如何实现？

Answer 1

据我了解，您的问题是如何实现文本框颜色使用systemcolors.control的默认值的视觉状态。 /code>状态和不同的自定义颜色时。

我知道的最简单方法是处理readonlychanged textbox控件的事件。例如：

public Form1()
{
    InitializeComponent();
    textBox2.ReadOnlyChanged += (sender, e) =>
    {
        textBox2.BackColor = textBox2.ReadOnly ? SystemColors.Control : Color.Blue;
    };
}

并在设置自定义背景颜色时首先检查状态：

private void button3_Click(object sender, EventArgs e)
{
    textBox2.BackColor = textBox2.ReadOnly ? SystemColors.Control : Color.Blue;
}

Answer 2

好吧，显然，由于“原因”，没有“光滑”的方法来实现这一目标，但是我确实发现，如果您设置了backcolor = color.empty。这是由于TextBoxBase中的不变代码造成的：

       public override Color BackColor {
        get {
            if (ShouldSerializeBackColor()) {
                return base.BackColor;
            }
            else if (this.ReadOnly) {
                return SystemColors.Control;
            } else {
                return SystemColors.Window;
            }
        }
        set {
            base.BackColor = value;
        }
    }

如果您将背色设置为color。这并不漂亮，但至少它有效。