如何在Windows窗体(C#)中动态添加组合框并将其绑定到sql数据库中的表的列

Question

我的Windows窗体有一个ADD按钮,每次单击后都会在窗体中添加一个组合框.问题是,我无法在运行时将其绑定到表列.使用现有数据绑定源在所有组合框中选择相同的值.我在C#中编码

这是示例代码:

ComboBox ocbNext = new ComboBox();
//HAVE set the rest of the properties right, the problem is with the databinding
ocbNext.DataSource = this.dummysubjectBindingSource;
ocbNext.DisplayMember = "sub_name";
ocbNext.ValueMember = "sub_name";
this.Controls.Add(ocbNext);

Answer 1

我在解决方案中添加了一个DataSet,并在设计器中删除了Employees表(来自Northwind),后者自动创建了employeesBindingSource.我在Form上放了一个组合框和一个按钮,然后设置了组合的DataSource和DataMember.然后我处理了一些事件:

    private void Form1_Load(object sender, EventArgs e)
    {
        this.employeesTableAdapter.Fill(this.dS.Employees);
    }

    private int _i = 0;
    private void button1_Click(object sender, EventArgs e)
    {
        ComboBox combo = new ComboBox();
        combo.DataSource = this.employeesBindingSource;
        combo.DisplayMember = this.dS.Tables[0].Columns[++_i].ColumnName;
        combo.Location = new Point(comboBox1.Location.X, comboBox1.Location.Y + comboBox1.Height * _i);
        this.Controls.Add(combo);
    }

因此,每次单击时,都会在前一个组合下动态地将新组合添加到表单上.组合也绑定到Employees表中的下一列(但是没有边界检查).

如你所见,这很容易.希望这可以帮助.

好的,所以这里有一个代码的变体,可以帮助你解决你在这个答案的评论中提出的其他问题.

它假设您有一个带有按钮的表单和带有表Employees的DataSet.在按钮上单击它会创建一个组合,并用数据填充它(Employees的Name列).每次添加组合时,它都会获得自己的数据副本(这对于能够一次从一个组合中删除项目非常重要).然后,每次在组合中选择一个值时,组合将被禁用,其他组合在其列表中没有选定的值.

  private int _i = 0;
    private void button1_Click(object sender, EventArgs e)
    {
        DataSet dataS = dS.Clone();
        this.employeesTableAdapter.Fill((DS.EmployeesDataTable)dataS.Tables[0]);
        BindingSource bindSource = new BindingSource(dataS, "Employees");

        ComboBox combo = new ComboBox();
        combo.Name = this.dS.Tables[0].Columns[0].ColumnName + (++_i).ToString();
        combo.DataSource = bindSource;
        combo.DisplayMember =  this.dS.Tables[0].Columns[1].ColumnName; //This column is the Name of Employee
        combo.Location = new Point(button1.Location.X, button1.Location.Y + combo.Height * _i);
        combo.SelectedIndexChanged += new EventHandler(comboBox_SelectedIndexChanged);
        this.Controls.Add(combo);
    }

    private void comboBox_SelectedIndexChanged(object sender, EventArgs e)
    {
        foreach (Control ctrl in this.Controls)
        {
            if (ctrl is ComboBox && ctrl != sender && ctrl.Enabled)
            {
                ((BindingSource)((ComboBox)ctrl).DataSource).RemoveAt(((ComboBox)sender).SelectedIndex);
            }
        }
        ((ComboBox)sender).Enabled = false;
    }

这非常接近您的要求,或者很容易适应您的期望.享受并请选择一个答案作为接受的答案.谢谢!