在 C# 中双击数据网格视图后复制的表单

Question

因此，我将尝试解释我希望我的应用程序做什么：

1）在主窗体中，我有一个TextBox和一个DataGridView。我将在TextBox中插入要搜索的内容，然后单击F1以打开将在另一个DataGridView中显示的第二种形式。

2）我将双击第二个表单DataGridView，该列值将从主表单显示在TextBox中。

3）之后，填充该TextBox，并根据该值，它将插入到主窗体中，DataGridView详细说明该值。

在第二个形式DataGridView中，我有一个双击事件：

private void dataGridView1_RowHeaderMouseDoubleClick(object sender, DataGridViewCellMouseEventArgs e)
{
    try
    {
        DataGridViewRow dr = dataGridView1.SelectedRows[0];
        this.Hide();
        frmPrincipal frm = new frmPrincipal();
        frm.Show();
        frm.txtCarga.Text = dr.Cells[0].Value.ToString();
        frm.txtCarga.Focus();
        frm.txtCarga.SelectAll();
    }
    catch (Exception ex)
    {
        MessageBox.Show("ErronDetalhes: " + ex.Message, "Erro", MessageBoxButtons.OK, MessageBoxIcon.Error);
    }
}

这是我在主形式中调用第二种形式的时候：

private void txtCarga_KeyDown(object sender, KeyEventArgs e)
        {
            if (e.KeyCode == Keys.F1)
            {
                this.Hide();
                frmPesquisa frmP = new frmPesquisa();
                frmP.Show();
                con = new SqlConnection(cs.DBConnP);
                con.Open();
                string querySelect = @"SELECT CL.Cargs
                                    FROM CargsCab CC (NOLOCK)
                                    INNER JOIN CargsLin CL (NOLOCK) ON CC.Cargs = CL.Cargs
                                    INNER JOIN Stock S (NOLOCK) ON CL.Code = S.Code
                                    WHERE CC.Date >= GETDATE() - 120 AND CL.State NOT IN ('F', 'A') AND S.Type = 'P' 
                                    AND CC.TypeB = 'OCS' AND CL.Cargs LIKE '%" + txtCargs.Text + "%' GROUP BY CL.Cargs ORDER BY CL.Cargs DESC";
                cmd = new SqlCommand(querySelect);
                cmd.Connection = con;
                cmd.Parameters.Add(new SqlParameter("@Cargs", SqlDbType.NChar, 20, "CL.Cargs"));
                cmd.Parameters["@Cargs"].Value = txtCargs.Text;
                SqlDataAdapter da = new SqlDataAdapter(cmd);
                DataSet ds = new DataSet();
                da.Fill(ds, "CargsCab");
                frmP.dataGridView1.DataSource = ds.Tables["CargsCab"].DefaultView;
                txtCarga.SelectAll();
                con.Close();
            }
        }

这里的问题是，如果我使用该frm.Show();它将打开一个新的 frmPrincipal 表单，但我已经有一个。如果我注释frm.Show();则代码将不会执行，但不会显示错误。基本上该值不会显示在TextBox中。

我该怎么办？

Answer 1

我已经根据您的新编辑更新了我的答案

public class frmPrincipal
{
    // ....
    // rest of your form Code
    private void txtCarga_KeyDown(object sender, KeyEventArgs e)
    {
        if (e.KeyCode == Keys.F1)
        {
            this.Hide();
            frmPesquisa frmP = new frmPesquisa(this); // Pass a reference to this form
            frmP.Show();
            con = new SqlConnection(cs.DBConnP);
            con.Open();
            string querySelect = @"SELECT CL.Cargs
                                FROM CargsCab CC (NOLOCK)
                                INNER JOIN CargsLin CL (NOLOCK) ON CC.Cargs = CL.Cargs
                                INNER JOIN Stock S (NOLOCK) ON CL.Code = S.Code
                                WHERE CC.Date >= GETDATE() - 120 AND CL.State NOT IN ('F', 'A') AND S.Type = 'P' 
                                AND CC.TypeB = 'OCS' AND CL.Cargs LIKE '%" + txtCargs.Text + "%' GROUP BY CL.Cargs ORDER BY CL.Cargs DESC";
            cmd = new SqlCommand(querySelect);
            cmd.Connection = con;
            cmd.Parameters.Add(new SqlParameter("@Cargs", SqlDbType.NChar, 20, "CL.Cargs"));
            cmd.Parameters["@Cargs"].Value = txtCargs.Text;
            SqlDataAdapter da = new SqlDataAdapter(cmd);
            DataSet ds = new DataSet();
            da.Fill(ds, "CargsCab");
            frmP.dataGridView1.DataSource = ds.Tables["CargsCab"].DefaultView;
            txtCarga.SelectAll();
            con.Close();
        }
    }
}
public class frmPesquisa
{
    private frmPrincipal frmP;
    public frmPesquisa()
    {
        InitializeComponent(); // Default constructor
    }
    public frmPesquisa(frmPrincipal frmP) : this()
    {
        this.frmP = frmP;
    }
    private void dataGridView1_RowHeaderMouseDoubleClick(object sender, DataGridViewCellMouseEventArgs e)
    {
        try
        {
            DataGridViewRow dr = dataGridView1.SelectedRows[0];
            this.Hide();
            // If we have a reference to the main form, then show it
            // and set the txtCarga text
            if (this.frmP != null && !this.frmP.IsDiposed)
            {
                frmP.Show();
                frmP.txtCarga.Text = dr.Cells[0].Value.ToString();
                frmP.txtCarga.Focus();
                frmP.txtCarga.SelectAll();
            }
        }
        catch (Exception ex)
        {
            MessageBox.Show("ErronDetalhes: " + ex.Message, "Erro", MessageBoxButtons.OK, MessageBoxIcon.Error);
        }
    }
}