將項添加到數組時C＃nullReferenceException

Question

當我嘗試將項添加到數組時，我收到此錯誤，它添加沒有問題1項，但當有更多它停止並給出錯誤。

nullReferenceException未將對象引用設置為對象的實例。

public void btnZoek_Click(object sender, EventArgs e)
{
    if (search == false)
    {
        OpenFiles[index] = new AddFileClass();

        System.IO.DirectoryInfo di = new System.IO.DirectoryInfo(Application.StartupPath + "\\Saves");
        System.IO.FileInfo[] rgFiles = di.GetFiles("*.txt");//add only .txt files

        foreach (System.IO.FileInfo fi in rgFiles)
        {
            OpenFiles[index].setNewItem(index, fi.Name, Convert.ToString(di));//send the info to the array (Number, filename, filelocation)
            index++;
        }
        search = true; //make sure it doens'nt add something double
    }
    if (search == true)
    {
        Form3_Zoeken_ frmSearch = new Form3_Zoeken_();
        frmSearch.Show();
    }
}

這是一張圖片，顯示fi（FileInfo）和di（DirectoryInfo）不為空：

Answer 1

在我看來，你永遠不會初始化OpenFiles數組項 - 也就是說，你只是初始化第一項。

嘗試這個：

public void btnZoek_Click(object sender, EventArgs e)
{
    if (search == false)
    {
        System.IO.DirectoryInfo di = new System.IO.DirectoryInfo(Application.StartupPath + "\\Saves");
        System.IO.FileInfo[] rgFiles = di.GetFiles("*.txt");//add only .txt files

        foreach (System.IO.FileInfo fi in rgFiles)
        {
            OpenFiles[index] = new AddFileClass();
            OpenFiles[index].setNewItem(index, fi.Name, Convert.ToString(di));//send the info to the array (Number, filename, filelocation)
            index++;
        }
        search = true; //make sure it doens'nt add something double
    }
    if (search == true)
    {
        Form3_Zoeken_ frmSearch = new Form3_Zoeken_();
        frmSearch.Show();
    }
}