C# 必须声明标量变量“@Stockno”

我有两种不同形式的addstock表单和viewstocks表单

当我在addstock表单中添加库存号和详细信息并返回时，请按viewstock表单中的刷新按钮；新记录将显示在viewstock表单中

viewstock表单还具有“删除”按钮

当我选择行并按delete键时，会出现此错误

必须声明标量变量@Stockno

我需要打电话。请帮忙

private void bunifuFlatButton3_Click(object sender, EventArgs e)
{
    try 
    {
        conn.Close();
        conn.Open();

        String DeleteQuery = "delete from Stocks_Item where Stock_code = (@Stockno)";

        SqlDataAdapter execute = new SqlDataAdapter(DeleteQuery, conn);
        execute.SelectCommand.ExecuteNonQuery();

        MessageBox.Show("You've deleted successfully!", "Successful Message", MessageBoxButtons.OK, MessageBoxIcon.Information);

        conn.Close();
        cmd.ExecuteNonQuery();

        SqlDataAdapter data = new SqlDataAdapter("Select * from Stocks_Item", conn);
        DataTable dt = new DataTable();
        data.Fill(dt);

        dataGridView1.DataSource = dt;
    }
    catch (Exception ex)
    {
        MessageBox.Show(ex.Message, "Error Message", MessageBoxButtons.OK, MessageBoxIcon.Error);
    }
}

要删除某些内容时，不应使用SqlDataAdapter—使用独立的SqlCommand—如下所示：

private void bunifuFlatButton3_Click(object sender, EventArgs e)
{
    try 
    {
        conn.Close();

        string DeleteQuery = "delete from Stocks_Item where Stock_code = @Stockno";

        SqlCommand cmdDelete = new SqlCommand(DeleteQuery, conn);
        -- add the parameter!
        cmdDelete.Parameters.Add("@stockno", SqlDbType.Int).Value = (provide the value for `@stockno` here!);

        // open connection, execute command, close connection
        conn.Open();
        cmdDelete.ExecuteNonQuery();
        conn.Close();

        MessageBox.Show("You've deleted successfully!", "Successful Message", MessageBoxButtons.OK, MessageBoxIcon.Information);
        .....
    }
}

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您甚至还没有在删除中添加要比较的实际值。我觉得你写的代码你并不完全理解。