AJAX折線圖中Asp.Net

Question

試圖建立在asp.net的AJAX線圖時，我有一些問題。我想要做的是從下拉列表中選擇一個類別，然後折線圖將顯示每個類別每個月發出的產品總和。這是在表示層代碼：

protected void ddlCategory_SelectedIndexChanged(object sender, EventArgs e) 
{ 
    string categoryName = ddlCategory.SelectedItem.ToString(); 
    string deliveryDate = ""; 
    decimal[] totalQuantity; 

    List<ProductPacking> catSumList = new List<ProductPacking>(); 
    for (int count = 0; count < catSumList.Count; count++) 
    { 
     deliveryDate = catSumList[count].deliveryDate; 
     totalQuantity = Convert.ToDecimal(catSumList[count].productQuantity); 
    } 
    lcCategory.Series.Add(new AjaxControlToolkit.LineChartSeries { Data = totalQuantity }); 
    lcCategory.CategoriesAxis = string.Join(",", deliveryDate); 
    lcCategory.ChartTitle = string.Format("", deliveryDate); 
    lcCategory.Visible = true; 
} 

而在業務邏輯層代碼：

public List<ProductPacking> getSumCategoryByMonth(string categoryName) 
{ 
    List<ProductPacking> ft = new List<ProductPacking>(); 
    ft = prodPack.getSumCategoryByMonth(categoryName); 
    return ft; 
} 

而且在數據訪問層的代碼：

public List<ProductPacking> getSumCategoryByMonth(string categoryName) 
{ 
    List<ProductPacking> ft = new List<ProductPacking>(); 

    using (var connection = new SqlConnection(FoodBankDB.connectionString)) 
    { 
     SqlCommand command = new SqlCommand("SELECT SUM(Convert(INT, ddi.productQuantity)) AS totalQuantity, pc.categoryName, d.deliveryDate FROM dbo.DistributionDistributedItems ddi " + 
      " INNER JOIN dbo.ProductVariants pv ON ddi.productVariant = pv.id " + 
      " INNER JOIN dbo.Products p ON pv.product = p.id " + 
      " INNER JOIN dbo.ProductCategories pc ON p.productCategory = pc.id " + 
      " INNER JOIN dbo.Distributions d ON ddi.distribution = d.id " + 
      " WHERE categoryName = '" + categoryName + "'" + 
      " GROUP BY pc.categoryName, d.deliveryDate", connection); 
     connection.Open(); 
     using (var dr = command.ExecuteReader()) 
     { 
      while (dr.Read()) 
      { 
       ft.Add(new ProductPacking(Convert.ToInt32(dr["totalQuantity"].ToString()), dr["deliveryDate"].ToString())); 
      } 
     } 
    } 
    return ft; 
} 

然而，有一個錯誤在周圍的

totalQuantity = Convert.ToDecimal(catSumList[count].productQuantity); 

表示層

一行。該錯誤消息是不能將隱式轉換類型十進制轉換爲十進制[]。我從這個網站稱：Line Chart In Asp.Net

我不知道如何根據我的情況解決這個問題。提前致謝。

Answer 1

你 catSumList後

移動的totalQuantity的聲明，並改成這樣：

List<ProductPacking> catSumList = new List<ProductPacking>(); 
catSumList = BLL.getSumCategoryByMonth("Some Category"); 
decimal[] totalQuantity = new decimal[catSumList.Count]; 

然後在for塊進入counttotalQuantity使用的索引值：

for (int count = 0; count < catSumList.Count; count++) 
{ 
    deliveryDate = catSumList[count].deliveryDate; 
    totalQuantity[count] = Convert.ToDecimal(catSumList[count].productQuantity); 
}