c# - 我需要了解为什么当我向标签添加值时我得到空值？

Question

当我检查 CheckBoxList 中的项目时，我正在制作一个表单，我想从 SQL table 中获取哪些列，我得到一个 new Form() 然后我想添加值并将它们添加到 SQL。除了最后一个，我得到空值。任何建议为什么会这样？

 private void Button1_Click(object sender, EventArgs e)
    {
        query = $"INSERT INTO {DM.comboBox1.SelectedItem} Values(";


        for (int i = 0; i <DM.checkedListBox1.CheckedIndices.Count; i++)
        {
            if (DM.checkedListBox1.CheckedIndices.Count == i + 1)
            {
                query += "'" + txtBox[i].Text + "')";
                break;
            }
            query += "'" + txtBox[i].Text + "'";
            query += ",";

        }
        myQuery = query;

        Fm1.conn = new SqlConnection($"Server = {Fm1.ServerBox.Text }; Database = { Fm1.DBBox.Text}; Trusted_Connection = True");
        Fm1.cmd = new SqlCommand(myQuery, Fm1.conn);
        Fm1.conn.Open();
        Fm1.cmd.ExecuteNonQuery();
        Fm1.conn.Close();

    }

    private void Test_Load(object sender, EventArgs e)
    {
        TableLayoutPanel tableLayoutPanel = new TableLayoutPanel() { AutoSize = true };
        tableLayoutPanel.ColumnStyles.Add(new ColumnStyle(SizeType.AutoSize));
        int n = 0;

        for (int i = 0; i < DM.checkedListBox1.CheckedItems.Count; i++)
        {

            txtBox = new TextBox[DM.checkedListBox1.CheckedItems.Count];
            labels = new Label[DM.checkedListBox1.CheckedItems.Count];

            labels[i] = new Label();
            for (int j = i; j < DM.dataGridView1.Columns.Count; j++)
            {
                if (DM.dataGridView1.Columns[j].Visible)
                {
                    labels[i].Text = DM.dataGridView1.Columns[j].HeaderText;
                    break;
                }
            }
            tableLayoutPanel.RowStyles.Add(new RowStyle(SizeType.AutoSize));
            tableLayoutPanel.SetCellPosition(labels[i], new TableLayoutPanelCellPosition(0, n++));
            tableLayoutPanel.Controls.Add(labels[i]);

            txtBox[i] = new TextBox();
            tableLayoutPanel.RowStyles.Add(new RowStyle(SizeType.AutoSize));
            tableLayoutPanel.SetCellPosition(txtBox[i], new TableLayoutPanelCellPosition(0, n++));
            tableLayoutPanel.Controls.Add(txtBox[i]);
        }

       Controls.Add(tableLayoutPanel);
    }

Answer 1

无法评论，因为没有 50。上面的 Amy 是正确的。

删除这些行并重试:

labels = new Label[DM.checkedListBox1.CheckedItems.Count];
txtBox = new TextBox[DM.checkedListBox1.CheckedItems.Count];

因评论而更新。