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“使用复选框动态添加组合框”

winforms c#

DrakeMurdoch · 技术社区 · 6 年前

单击复选框时,我正在尝试添加组合框。

我使用的代码如下。现在,我可以让它围绕已经存在的组合框移动,但它不会创建新的组合框。

        private void checkBox1_CheckedChanged(object sender, EventArgs e)
    {
        // Determine the CheckState of the check box.  
        if (checkBox1.CheckState == CheckState.Checked)
        {  

            combo.Items.AddRange(new object[] {
                "Item 1",
                "Item 2",
                "Item 3",
                "Item 4",
                "item 5",
                "Item 6"});
            combo.Location = new System.Drawing.Point(19, 123);
            combo.Name = "combo";
            combo.Size = new System.Drawing.Size(121, 21);
            combo.TabIndex = 0;
            combo.SelectedIndexChanged += new System.EventHandler(this.combo_SelectedIndexChanged);
            combo.BringToFront();

            this.AllowDrop = false;
        }
    }

    private void checkBox1_Click(object sender, System.EventArgs e)
    {
        switch (checkBox1.CheckState)
        {
            case CheckState.Checked:
                ComboBox combo = new ComboBox();
                Controls.Add(combo);
                break;
            case CheckState.Unchecked:

                break;
            case CheckState.Indeterminate:

                break;
        }
    }

1 回复 | 直到 6 年前

DrakeMurdoch 6 年前

解决问题的方法是意识到你将陈述放在哪个函数中。组合框的设置(范围、位置等)将位于 CheckChanged 在 if checked 条件。这些会和 groupbox.controls.add(); 和 combo.BringToFront(); 以防万一,它会落在什么东西后面。

private void checkBox1_CheckedChanged(object sender, EventArgs e)
    {
        // Determine the CheckState of the check box.  
        if (checkBox1.CheckState == CheckState.Checked)
        {
            groupBox1.Controls.Add(combo);
            combo.Items.AddRange(new object[] {
                "Item 1",
                "Item 2",
                "Item 3",
                "Item 4",
                "Item 5",
                "Item 6"});
            combo.Location = new System.Drawing.Point(19, 123);
            combo.Name = "combo";
            combo.Size = new System.Drawing.Size(121, 21);
            combo.TabIndex = 0;
            combo.SelectedIndexChanged += new System.EventHandler(this.combo_SelectedIndexChanged);
            combo.BringToFront();

            this.AllowDrop = false;
}

同时,在 Click 函数,必须实例化组合框并添加它。

    private void checkBox1_Click(object sender, System.EventArgs e)
    {
        switch (checkBox1.CheckState)
        {
            case CheckState.Checked:
                ComboBox combo = new ComboBox();
                Controls.Add(combo);
                break;
            case CheckState.Unchecked:

                break;
            case CheckState.Indeterminate:

                break;
        }
    }

如果您想在取消选中复选框后去掉组合框,只需添加

        if (checkBox1.CheckState == CheckState.Unchecked)
        {
            groupBox1.Controls.Remove(combo);
            Controls.Remove(combo);
            combo.Items.Clear();
        }

进入 private void checkBox1_CheckedChanged(object sender, EventArgs e) 功能。一定要放 combo.items.Clear() 或者它会将组合框的新实例的范围添加到旧实例中。