我得到错误“索引超出范围。必须是非负数且小于集合的大小。参数名称：index&quot。。我会解决它吗？ [英] I get error "Index was out of range. Must be non-negative and less than the size of the collection. Parameter name: index".How I'll solve it?

问题描述

private void BindGrid()
    {
        int selectedRowIndex = GridView1.SelectedIndex;
        int pId = (int)GridView1.DataKeys[selectedRowIndex].Value;//I get error in this line.
        SqlConnection conn;
        SqlCommand comm;
        SqlDataReader reader;
        string connectionString =
        ConfigurationManager.ConnectionStrings[
        "ConnectionString"].ConnectionString;
        conn = new SqlConnection(connectionString);
        comm = new SqlCommand("SELECT ProductId, ProductName, Price FROM Product " +
        "WHERE ProductId=@ProductId", conn);
        comm.Parameters.Add("ProductId", SqlDbType.Int);
        comm.Parameters["ProductId"].Value = pId;
        try
        {
            conn.Open();
            reader = comm.ExecuteReader();
            employeeDetails.DataSource = reader;
            employeeDetails.DataKeyNames = new string[] { "ProductId" };
            employeeDetails.DataBind();
            reader.Close();
        }
        finally
        {
            conn.Close();
        }
    }

推荐答案

来自文档 [ ^ ]：

From the documentation[^]:

GridView控件中所选行的从零开始的索引。 默认值为-1，表示当前没有选择行。

The zero-based index of the selected row in a GridView control. The default is -1, which indicates that no row is currently selected.

您可以这样修改代码：

You could modify your code this way:

private void BindGrid()
    {
        int selectedRowIndex = GridView1.SelectedIndex;
        if ( selectedRowIndex < 0) return;
        //...

GridView1.SelectedIndex = -1因为在gridview中没有选择索引



尝试以下代码...



private void BindGrid（）

{

int selectedRowIndex = GridView1.SelectedIndex;

if（selectedRowIndex> 0 ）

{

int pId =（int）GridView1.DataKeys [selectedRowIndex] .Value;

SqlConnection conn;

SqlCommand comm;

SqlDataReader reader;

string connectionString =

ConfigurationManager.ConnectionStrings [

ConnectionString ] .ConnectionString;

conn = new SqlConnection（connectionString）;

comm = new SqlCommand（SELECT ProductId，ProductName，Price FROM Product+

WHERE ProductId = @ ProductId，conn）;

comm.Parameters.Add（ProductId，SqlDbType.Int）;

comm.Parameters [ProductId]。Value = pId;

try

{

conn.Open（）;

reader = comm.ExecuteReader（）;

employeeDetails.DataSource = reader ;

employeeDetails.DataKeyNames = new string [] {ProductId};

employeeDetails.DataBind（）;

reader.Close（） ;

}

终于

{

conn.Close（）;

}

}

GridView1.SelectedIndex = -1 because no index is selected in the gridview

try the below code...

private void BindGrid()
{
int selectedRowIndex = GridView1.SelectedIndex;
if(selectedRowIndex>0)
{
int pId = (int)GridView1.DataKeys[selectedRowIndex].Value;
SqlConnection conn;
SqlCommand comm;
SqlDataReader reader;
string connectionString =
ConfigurationManager.ConnectionStrings[
"ConnectionString"].ConnectionString;
conn = new SqlConnection(connectionString);
comm = new SqlCommand("SELECT ProductId, ProductName, Price FROM Product " +
"WHERE ProductId=@ProductId", conn);
comm.Parameters.Add("ProductId", SqlDbType.Int);
comm.Parameters["ProductId"].Value = pId;
try
{
conn.Open();
reader = comm.ExecuteReader();
employeeDetails.DataSource = reader;
employeeDetails.DataKeyNames = new string[] { "ProductId" };
employeeDetails.DataBind();
reader.Close();
}
finally
{
conn.Close();
}
}

}

}

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