我试图在一个消息框中列出所有组合框项目.但是我所得到的是每个项目都出现在自己的消息框中.我知道消息框需要在循环之外,但是当我这样做时,它说该变量未分配.任何帮助都会很棒.

私人无效displayYachtTypesToolStripMenuItem_Click(对象发送者,EventArgs e)
       {

       string yachtTypesString;

        for (int indexInteger = 0; indexInteger < typeComboBox.Items.Count; indexInteger++)

        {
            yachtTypesString=typeComboBox.Items[indexInteger].ToString();
            MessageBox.Show(yachtTypesString);
        }

       }

解决方法:

像这样做,

    StringBuilder yachtTypesString = new StringBuilder();
    for (int indexInteger = 0; indexInteger < typeComboBox.Items.Count; indexInteger++)
    {
        yachtTypesString.AppendLine(typeComboBox.Items[indexInteger].ToString());
    }
    MessageBox.Show(yachtTypesString.ToString());

注意：不要使用字符串进行字符串连接,请使用StringBuilder对象在字符串中创建新实例.