如何在页面加载时以编程方式从GridView1的第一行第4列单元格中选择数据并将其保存到C＃asp.net中的变量

Question

I am new to asp.net and C# web application development.

My question is: I have a GridView1 which is bound to a data source which is getting data from a SQL Server table.

Gridview1 has these columns:

• select(default select available in gridview to select row)
• time
• customer
• address
• longitude (visible = false)
• latitude (visible = false)

This data is also filtered and sorted by a drop down list date

What I want to do is when my page load the value of latitude and longitude column first row value get assigned to my variable lat and lng

This is what I am writing, basically the lat and lng variable will be used in my another function:

        Double lat, lng;
        lat = Convert.ToDouble(GridView1.Rows[1].Cells[4].Text);
        lng = Convert.ToDouble(GridView1.Rows[1].Cells[5].Text);
        GLatLng latlong = new GLatLng(lat, lng);
        GMap1.setCenter(latlong, 10);

The following exception is thrown:

Index was out of range. Must be non-negative and less than the size of the collection.

The gridview data is never null it always has some data

Answer 1

在访问行集合Gridview.Datasource = yourdatasource Gridview.bind（）之前，请确保将gridview绑定到数据源。

Answer 2

Try This

lat = Convert.ToDouble(GridView1.Rows[0].Cells[3].Text);

Because Gridview Rows and Cells are always start from 0 (Zero).

OR

best way is use .findControl() Method of Controls like below.

string lat = ((Label)GridView1.Rows[0].FindControl("labelID")).Text

But, for above code you have to take <asp:label> in <ItemTemplate> in your GridView