原帖及讨论：http://bbs.bccn.net/thread-167704-1-1.html

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*/ 出自： 编程中国  http://www.bccn.net
*/ 作者： C_B_Lu        QQ：184118549
*/ 时间： 2007-9-4  编程论坛首发
*/ 声明： 尊重作者劳动，转载请保留本段文字
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常有这种情况,在一个ComboBox控件的左侧,放一个TextBox控件,用于存放ComboBox所选项的值(即SelectedValue属性).
同时ComboBox控件还允许直接在其中输入内容来搜索.

        private void cbUnitName_SelectedIndexChanged(object sender, EventArgs e)
        {
            if ((cbUnitName.Text != "") && (cbClientName.SelectedIndex > -1))
            {
                tbUnitID.Text = cbUnitName.SelectedValue.ToString().Trim();
            }
        }

        private void cbUnitName_Validating(object sender, CancelEventArgs e)
        {
            if (currentState == state.Browse)
            {
                return;
            }
            errorProvider1.SetError(cbUnitName, "");
            string strUnitName = cbUnitName.Text.Trim();
            if (strUnitName == "")
            {
                tbUnitID.Text = cbUnitName.Text = "";
                return;
            }
            
            cbUnitName.SelectedIndex = cbUnitName.FindString(strUnitName);
            if (cbUnitName.SelectedIndex < 0)
            {
                errorProvider1.SetError(cbUnitName, "單位有誤,請重新輸入!");
                cbUnitName.SelectAll();
                cbUnitName.Focus();
                e.Cancel = true;
            }
        }