当我从其他表单中打开它时，组合框始终显示第一个值，而不是datagrid中的值

Question

我有一个包含两个组合框（cmbSection，cmbGrade）和两个文本框（txtName，txtSectionSize）的表单，我想从combobox和txtSectionSize中获取文本并将其放在txtName中，所以我的代码锁定像这样

 public partial class FRM_Item : Form
 {
    //public string State = "Add";
    BL.CLS_Item prd = new BL.CLS_Item();

    public FRM_Item()
    {
        InitializeComponent();

        cmbSection.DataSource = prd.Get_All_Items();
        cmbSection.DisplayMember = "Name_SectionType";
        cmbSection.ValueMember = "ID_SectionType";

        cmbGrade.DataSource = prd.Get_All_Grade();
        cmbGrade.DisplayMember = "Name_Grade";
        cmbGrade.ValueMember = "ID_Grade";
    }
private void cmbSection_SelectedIndexChanged(object sender, EventArgs e)
    {
        this.txtName.Text = cmbSection.Text + txtSectionSize.Text + "-" + cmbGrade.Text;
    }

    private void cmbGrade_SelectedIndexChanged(object sender, EventArgs e)
    {
        this.txtName.Text = cmbSection.Text + txtSectionSize.Text + "-" + cmbGrade.Text;

    }

    private void txtSectionSize_TextChanged(object sender, EventArgs e)
    {
        this.txtName.Text = cmbSection.Text + txtSectionSize.Text + "-" + cmbGrade.Text;
    }

当我打开表单时，我在txtName中得到System.Data.DataRowView，但是当我从组合框中选取任何文本时，我在文本框中获得了正确的值，我通过将这段代码移到表单加载中解决了这个问题

        private void FRM_Item_Load(object sender, EventArgs e)
    {
        cmbSection.DataSource = prd.Get_All_Items();
        cmbSection.DisplayMember = "Name_SectionType";
        cmbSection.ValueMember = "ID_SectionType";

        cmbGrade.DataSource = prd.Get_All_Grade();
        cmbGrade.DisplayMember = "Name_Grade";
        cmbGrade.ValueMember = "ID_Grade";
    }

当我从另一个窗体的按钮中打开此窗体时出现的问题，组合框始终显示第一个值，而不是datagrid的值

private void btnEdit_Click(object sender, EventArgs e)
    {
        FRM_Item frm = new FRM_Item();
        frm.txtName.Text = this.dataGridView1.CurrentRow.Cells[1].Value.ToString();
        frm.cmbSection.Text = this.dataGridView1.CurrentRow.Cells[2].Value.ToString();
        frm.txtSectionSize.Text = this.dataGridView1.CurrentRow.Cells[3].Value.ToString();
        frm.cmbGrade.Text = this.dataGridView1.CurrentRow.Cells[4].Value.ToString();

        frm.ShowDialog();
    }

我该如何解决这个问题

Answer 1

分配组合框之前，请先分配它们。 现在，它倒退了。

我建议将此代码移到子窗体构造函数或在尝试在父窗体中分配属性之前可以调用的方法。

    cmbSection.DataSource = prd.Get_All_Items();
    cmbSection.DisplayMember = "Name_SectionType";
    cmbSection.ValueMember = "ID_SectionType";

    cmbGrade.DataSource = prd.Get_All_Grade();
    cmbGrade.DisplayMember = "Name_Grade";
    cmbGrade.ValueMember = "ID_Grade";

至于将代码放入构造函数中的事件，如果您还没有完成构造函数，或者没有在设计器中拥有事件并在构造函数中明确地进行操作，则可以具有布尔属性以不运行事件代码填充组合框之后。