[英]How do I display a LineChart control ASP.NET?
I would like to display a Line Chart depending of the DropDownList control. 我想根据DropDownList控件显示一个折线图。
When I choose a value of this DropDown, the Line Chart display with the average of my value column group by the value of my DropDown. 当我选择此DropDown的值时,将显示折线图,其中包含我的值列组的平均值乘以我的DropDown的值。
The column Entite is a Varchar type and AvancementQuantitatifT1 is a decimal (3,2) type. Entite列是Varchar类型,而AvancementQuantitatifT1列是十进制(3,2)类型。
Nothing display when I choose a value of my DropDownList. 当我选择DropDownList的值时,什么也没有显示。
This is my code behind : 这是我的代码背后:
protected void entite_SelectedIndexChanged(object sender, EventArgs e)
{
string query = string.Format("select Entite, AVG(AvancementQuantitatifT1 * 100) FROM reponse WHERE Entite = '{0}' GROUP BY Entite", NomEntite.SelectedItem.Value);
DataTable dt = GetData(query);
string[] x = new string[dt.Rows.Count];
decimal[] y = new decimal[dt.Rows.Count];
for (int i = 0; i < dt.Rows.Count; i++)
{
x[i] = dt.Rows[i][0].ToString();
y[i] = Convert.ToInt32(dt.Rows[i][1]);
}
LineChart1.Series.Add(new AjaxControlToolkit.LineChartSeries { Data = y });
LineChart1.CategoriesAxis = string.Join(",", x);
LineChart1.ChartTitle = string.Format("{0}", NomEntite.SelectedItem.Value);
if (x.Length > 3)
{
LineChart1.ChartWidth = (x.Length * 75).ToString();
}
LineChart1.Visible = true;
}
My SQL Query works fine in SQL Management studio. 我的SQL查询在SQL Management Studio中工作正常。
EDIT 编辑
Screenshot of my dt table : http://i.stack.imgur.com/VotIt.png 我的dt表的屏幕截图: http : //i.stack.imgur.com/VotIt.png
First, modify/debug your query string: 首先,修改/调试查询字符串:
string query = "SELECT Entite, AVG(AvancementQuantitatifT1 * 100) As AvrVal FROM reponse WHERE Entite = '" + (sender As ComboBox).Text + "' GROUP BY Entite")
and check if DataTable dt
contains records (insert a breakpoint at line string[] x = new string[dt.Rows.Count]
, then move cursor over dt
and use TableVisualization option). 并检查
DataTable dt
包含记录(在string[] x = new string[dt.Rows.Count]
行处插入断点,然后将光标移到dt
并使用TableVisualization选项)。
Note: reponse - is it correct Table Name? 注意: 回应 -表格名称正确吗?
The rest will depend on the result of this important step (make sure that DataTable dt
indeed contains records and is not null
; it seems that it's null based on your screenshot), Rgds, 其余的将取决于这一重要步骤的结果(确保
DataTable dt
确实包含记录并且不为null
;根据您的屏幕快照,它似乎为null),Rgds,
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