怎么样通过代码实现类似IE浏览器地址栏ComboBox的效果。

可以对comboBox进行如下的设置就可以了：
this.comboBox1.AutoCompleteMode = System.Windows.Forms.AutoCompleteMode.Suggest;
this.comboBox1.AutoCompleteSource = System.Windows.Forms.AutoCompleteSource.AllUrl;

不但这个控件可以这样用，TextBox也可以这样用：
this.textBox1.AutoCompleteMode = System.Windows.Forms.AutoCompleteMode.Suggest;
this.textBox1.AutoCompleteSource = System.Windows.Forms.AutoCompleteSource.AllUrl;



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private void button1_Click(object sender, EventArgs e)
        {
            Uri url = new Uri(this.textBox1.Text);
            this.webBrowser1.Url = url;
        }