Question

假设我有一个表格，有人可以列出多人姓名及其州和市？

假设我已经拥有数据库中的所有州/城市。（每个州的表格，每个表中列出的城市）

“名称”字段将是TextBox。和国家＆amp;城市字段将是ComboBox（DropDownLists）。

表格中已存在一行（用于输入一个人）。但我希望用户能够通过按“添加人员”按钮动态添加条目行。

下一步是我在努力的地方。在每个动态添加的字段行中，我希望根据在第一个组合框中选择的状态来填充第二个ComboBox（Cities）。此外，在选择State ComboBox之前，Cities ComboBox将保持禁用状态。

我的代码看起来像这样：

    public ComboBox cbState;
    public ComboBox cbCities;
    public static int NumberOfPeople = 1;


    private void btnAddNewPerson_Click(object sender, EventArgs e)
    {

        NumberOfPeople++;

        TextBox txtPerson = new TextBox();
        txtPerson.Name = "Person" + NumberOfPeople;
        Panel.Controls.Add(txtPerson);

        //  ADD State ComboBox
        cbState = new ComboBox();
        cbState.Name = "State" + NumberOfPeople;
        cbState.Enabled = true;
        cbState.DropDownStyle = ComboBoxStyle.DropDownList;
        Panel.Controls.Add(cbState);

        //  ADD City ComboBox
        cbCity = new ComboBox();
        cbCity.Name = "City" + NumberOfPeople;
        cbCity.DropDownStyle = ComboBoxStyle.DropDownList;
        cbCity.Enabled = false;
        cbCity.SelectedValueChanged += new System.EventHandler(this.ChangeState);
        Panel.Controls.Add(cbCity);

    }

    private void ChangeState(object sender, EventArgs e)
    {

       ..... Don't know how to properly identify the City ComboBox that is in the same row as the State ComboBox that was just changed, and manipulate/populate it.....

    }

任何人都能帮我解决这个问题吗？

我非常感谢!!

Answer 1

你可以使用字典

Dictionary<ComboBox,ComboBox> CityToStateMap = new Dictionary<ComboBox,ComboBox>();

然后当你添加一行

CityToStateMap[cbState] = cbCity;

然后当你改变状态

ComboBox city = CityToStateMap[(ComboBox)sender];

Answer 2

首先，我将创建一个包含一行所有控件的附加类（例如，名称为Row）。因此，您可以将一个人的控件封装在一个对象中您的Form类获取此类行对象的列表成员，如
List<Row> _rows = new List<Row>();。

在该类 Row 的构造函数中，您可以创建一行的控件，并将事件处理程序分配给组合框控件的SelectedValueChanged事件。

Answer 3

您可以使用Control.Tag将数据对象附加到控件。请参阅示例中控件如何相互引入。

private void btnAddNewPerson_Click( object sender, EventArgs e )
{
    AddPersonRow();
}

private void AddPersonRow()
{
    // Create combo boxes
    ComboBox cbCity = new ComboBox();
    ComboBox cbState = new ComboBox();

    // Introduce them to each other
    cbCity.Tag = cbState;
    cbState.Tag = cbCity;

    //  ADD State ComboBox
    cbState.Name = "State" + NumberOfPeople;
    cbState.Enabled = true;
    cbState.DropDownStyle = ComboBoxStyle.DropDownList;
    cbState.SelectedValueChanged += new EventHandler( cbState_SelectedValueChanged );
    panel.Controls.Add( cbState );

    // Populate the states sombo
    PopulateStateCombo( cbState );

    //  ADD City ComboBox
    cbCity.Name = "City" + NumberOfPeople;
    cbCity.DropDownStyle = ComboBoxStyle.DropDownList;
    cbCity.Enabled = false;
    cbCity.SelectedValueChanged += new EventHandler(cbCity_SelectedValueChanged);
    panel.Controls.Add( cbCity );
}

void cbState_SelectedValueChanged( object sender, EventArgs e )
{
    ComboBox cbState = sender as ComboBox;
    ComboBox cbCity = cbState.Tag as ComboBox;

    cbCity.Enabled = true;

    // .. Go ahead and populate cbCity by cbState's selected value ..
}

void cbCity_SelectedValueChanged( object sender, EventArgs e )
{
    // Up to you...
}

请注意，您可以创建一个包含ComboBox，TextBox控件，行号等的类，而不是与其他ComboBox握手，然后将所有这些控件的Tag设置为类本身。 / p>

public class PersonRow
{
    public int RowNum { get; private set; }
    public TextBox NameTextBox { get; private set; }
    public ComboBox CityCombo { get; private set; }
    public ComboBox StateCombo { get; private set; }

    public PersonRow( int rowNum )
    {
        RowNum = rowNum;

        // Create the controls
        NameTextBox = new TextBox();
        CityCombo = new ComboBox();
        StateCombo = new ComboBox();

        // Bind them to this instance
        NameTextBox.Tag = this;
        CityCombo.Tag = this;
        StateCombo.Tag = this;

        //.. continue as in the prev. example..
    }
}

Answer 4

首先，您应该找到要操作的组合框的名称。

然后您可以在面板中搜索具有我们刚刚找到的名称的控件，然后您可以按照自己的意愿进行操作。

这是

的代码

    private void ChangeState(object sender,EventArgs e){
        ComboBox stateComboBox= (ComboBox)sender;
        //find the name of target City ComboBox
        string cityComboName = "City"+stateComboBox.Name.Substring(5); // 5 is the Length of 'State'
        ComboBox cityComboBox=null;
        foreach(Control cntrl in panel1.Controls){
            if (cntrl.Name == cityComboName) {
                cityComboBox= (ComboBox)cntrl;
                break;
            }
        }
        if (cityComboBox!= null) {
            cityComboBox.Enabled = true;
            // now you have the both cityComboBox and stateComboBox Of the same Row
        }
    }

如何操作动态创建的控件？

4 个答案: