找不到第0列。 [英] Cannot find column 0.

问题描述

private void txtAdd_KeyDown(object sender, KeyEventArgs e)
{
    if (e.KeyCode == Keys.Enter)
    {
        if (txtAdd.Text != string.Empty && txtSahr.Text != string.Empty)
        {

            DataRow r = dt.NewRow();

            r[0] = txtNameMada.Text;
            r[1] = txtSahr.Text;
            r[2] = txtAdd.Text;
            r[3] = txtAdd_all.Text;

            cleartext();

            dt.Rows.Add(r);
            dataGridView6.DataSource = dt;
            txtsum.Text =
                   (from DataGridViewRow row in dataGridView6.Rows
                    where row.Cells[3].FormattedValue.ToString() != string.Empty
                    select Convert.ToDouble(row.Cells[3].FormattedValue)).Sum().ToString("0,0");

        }
        else
        {
            MessageBox.Show("ادخال كمية من العدد");
            //  txtAdd_Karton.Focus();
            txtAdd.Clear();
            return;
        }
    }
}

我尝试了什么：

What I have tried:

Cannot find column 0.

推荐答案

如果此行发生错误：

r[0] = txtNameMada.Text;

然后表格是空的：它不包含任何列，因此没有数据。



因为它是一个类级变量，所以我首先看一下加载它的方法首先，因为它建立了表的模式 - 如果你在你的方法中创建一个名为dt的局部变量：

Then the table is empty: it contains no columns, and hence no data.

Since it is a class level variable, I'd start by looking at the method where you load it in the first place, because that establishes the schema for the table - and if you create a local variable called dt within your method:

private DataTable dt = new DataTable();
void MyMethod(void)
   {
   DataTable dt = new DataTable();
   myDataAdapter.Fill(dt);
   ...
   }

然后掩盖了类级别版本，它永远不会被任何模式填充，更不用说数据了。

Then that masks the class level version and it never gets filled with any schema, much less data.

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