Question

我正在继续上一个问题，因为我从来没有得到完整的答复。 Reference previous object created in loop to update SQL

基本上，我已将语法更改为以下内容，但有两个问题：

复选框实际上不会出现。
在saveOrderBtn_Click循环中，我收到错误消息“当前上下文中不存在名称'myBoxes'”。这是在“if”语句行。

我无法使用Controls.Add（myCheckBox）;当你进行更新时，它会根据循环中创建的最后一个复选框更新SQL中的所有内容 - 它不会计算每个复选框。

我还在学习C＃。非常感谢你的进步。

更新代码：

public partial class SelectUsers : Form { 

// DECLARE THE myCheckBox
private CheckBox myCheckBox;

public SelectUsers()
{
    InitializeComponent();
}

private void SelectUsers_Load(object sender, EventArgs e)
{
    DataSet ds = myconnection.runSelect(new DataSet(), "THE SELECT");

    int xAxisCheckbox = 40;
    int yAxisCheckbox = 50;

    for (int i = 0; i < ds.Tables[0].Rows.Count; i++)
    {
        // CHANGED List<CheckBox> myBoxes LINE
        List<CheckBox> myBoxes = new List<CheckBox>();

        myCheckBox = new CheckBox();
        myCheckBox.Location = new Point(xAxisCheckbox, yAxisCheckbox);
        myCheckBox.Size = new Size(120, 20);
        myCheckBox.Text = ds.Tables[0].Rows[i]["FullName"].ToString();
        myCheckBox.Checked = (bool)ds.Tables[0].Rows[i]["InOperation"];
        yAxisCheckbox = yAxisCheckbox + 80;

        // THIS SHOULD ADD/RENDER EACH CHECKBOX, BUT IT DOESN'T
        myBoxes.Add(myCheckBox);
    }
}

private void saveBtn_Click(object sender, EventArgs e)
{
    DataSet ds = myconnection.runSelect(new DataSet(), "THE SELECT");

    for (int i = 0; i < ds.Tables[0].Rows.Count; i++)
    {
        userID = (int)ds.Tables[0].Rows[i]["UserID"];
        if (myBoxes[i].Checked)
        {
            myconnection.runUpdate("UPDATE Users SET InOperation = 1, OperationOrder = CASE WHEN OperationOrder = 1 THEN 1 ELSE CASE WHEN InOperation=1 THEN OperationOrder ELSE (SELECT COUNT(*)+1 FROM Users WHERE InOperation=1 AND OperationOrder > 0) END END WHERE UserID=" + userID);
            myconnection.runUpdate("UPDATE Users SET OperationOrder = CASE WHEN OperationOrder = 0 THEN (SELECT COUNT(*) FROM Users WHERE InOperation=1) ELSE OperationOrder END WHERE InOperation=1");
        }
        else
        {
            myconnection.runUpdate("UPDATE Users SET InOperation = 0, OperationOrder = 0 WHERE UserID=" + userID);
            myconnection.runUpdate("UPDATE Users SET OperationOrder = CASE WHEN OperationOrder -1 = 0 THEN (SELECT COUNT(*) FROM Users WHERE InOperation=1) ELSE OperationOrder -1 END WHERE InOperation=1");
        }
    }
}
}

Answer 1

阅读编程书籍后，我发现你没有像这样创建一个数组，它是通过以下方式完成的：

// Global
CheckBox[] myCheckBox;
DataSet ds;

private void SelectUsers_Load(object sender, EventArgs e) {

    ds = myconnection.runSelect(new DataSet(), "THE SELECT");

    int xAxisCheckbox = 40;
    int yAxisCheckbox = 50;

    // Create the CheckBox array (amount based on number of rows)
    myBoxes = new CheckBox[ds.Tables[0].Rows.Count];

    for (int i = 0; i < ds.Tables[0].Rows.Count; i++)
    {
        // Create a new Checkbox
        myCheckBox[i] = new CheckBox();

        myCheckBox.Location = new Point(xAxisCheckbox, yAxisCheckbox);
        myCheckBox.Size = new Size(120, 20);
        myCheckBox.Text = ds.Tables[0].Rows[i]["FullName"].ToString();
        myCheckBox.Checked = (bool)ds.Tables[0].Rows[i]["InOperation"];
        yAxisCheckbox = yAxisCheckbox + 80;

        // Add the Checkbox
        Controls.Add(myCheckBox[i]);
    }
}

private void saveBtn_Click(object sender, EventArgs e) {
    for (int i = 0; i < ds.Tables[0].Rows.Count; i++)
    {
        userID = (int)ds.Tables[0].Rows[i]["UserID"];

        if (myBoxes[i].Checked)
        {
            myconnection.runUpdate("UPDATE Users SET InOperation = 1, OperationOrder = CASE WHEN OperationOrder = 1 THEN 1 ELSE CASE WHEN InOperation=1 THEN OperationOrder ELSE (SELECT COUNT(*)+1 FROM Users WHERE InOperation=1 AND OperationOrder > 0) END END WHERE UserID=" + userID);
            myconnection.runUpdate("UPDATE Users SET OperationOrder = CASE WHEN OperationOrder = 0 THEN (SELECT COUNT(*) FROM Users WHERE InOperation=1) ELSE OperationOrder END WHERE InOperation=1");
        }
        else
        {
            myconnection.runUpdate("UPDATE Users SET InOperation = 0, OperationOrder = 0 WHERE UserID=" + userID);
            myconnection.runUpdate("UPDATE Users SET OperationOrder = CASE WHEN OperationOrder -1 = 0 THEN (SELECT COUNT(*) FROM Users WHERE InOperation=1) ELSE OperationOrder -1 END WHERE InOperation=1");
        }
    }
}

用于设置复选框的数组并将结果保存到SQL

1 个答案: