如何在asp.net中获取自动增量id# [英] how to get autoincrement id in asp.net c#
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问题描述
请一些人告诉我如何在asp.net c#中获取autoincreamented id,我写代码却抛出错误
不能隐式转换类型'对象' 'int'。存在显式转换(您是否错过演员表?)
和代码是
public void gen1()
{
con.Open ();
int a = 0 ;
SqlCommand com = new SqlCommand( select来自类别,con)的max(id);
a = com.ExecuteScalar();
TextBox4.Text = Convert.ToString(a);
con.Close();
}
请帮我纠正。 ..
解决方案
嗨Rani,
尝试更换
a = com.ExecuteScalar();
with
a = Conver。 ToInt32(com.ExecuteScalar());
检查 SqlCommand.ExecuteScalar方法 [ ^ ]。你需要将该对象强制转换为指定的类型。
它将会运作。
- -Amit
试试这个,
public void Autogenrate()
{
int r;
尝试
{
con = new SqlConnection( data source = XYZ; user id = ABC; password = ***; initial catalog = Detail);
con.Open();
SqlCommand cmd = new SqlCommand( 选择来自empp1的最大(id),con);
SqlDataReader dr = cmd.ExecuteReader();
if (dr.Read())
{
字符串 d = dr [ 0 ]。ToString();
if (d == )
{
id.Text = 1001; // 在文本框中设置名称为id的值
}
else
{
r = Convert.ToInt32(dr [ 0 跨度>]的ToString());
r = r + 1 ;
id.Text = r.ToString();
}
}
con.Close();
con.Open();
cmd.CommandText = insert empp1 values(' + id。文字+ ',' + txtName.Text + ',' + txtCity.Text + ')跨度>;
cmd.ExecuteNonQuery();
}
catch (例外情况)
{
Response.Write( < script> alert( + ex.Message + )< / script>);
}
最后
{
con.Close();
}
}
你可以在表格中增加id,
点击此处
pls some one tell that how to get autoincreamented id in asp.net c#, i write the code but it throws error
Cannot implicitly convert type 'object' to 'int'. An explicit conversion exists (are you missing a cast?)
and code is
public void gen1()
{
con.Open();
int a = 0;
SqlCommand com = new SqlCommand("select max(id) from Category", con);
a = com.ExecuteScalar();
TextBox4.Text = Convert.ToString(a);
con.Close();
}
pls help me to correct...
解决方案
Hi Rani,
Try replacing
a = com.ExecuteScalar();
with
a = Conver.ToInt32(com.ExecuteScalar());
Check SqlCommand.ExecuteScalar Method[^] which returns object. You need to cast that object to a specified type.
It'll work out.
--Amit
Try This,
public void Autogenrate() { int r; try { con = new SqlConnection("data source=XYZ; user id=ABC; password=***; initial catalog=Detail"); con.Open(); SqlCommand cmd = new SqlCommand("Select max(id) from empp1", con); SqlDataReader dr = cmd.ExecuteReader(); if (dr.Read()) { string d = dr[0].ToString(); if (d == "") { id.Text = "1001";//set the value in textbox which name is id } else { r = Convert.ToInt32(dr[0].ToString()); r = r + 1; id.Text = r.ToString(); } } con.Close(); con.Open(); cmd.CommandText = "insert empp1 values('" + id.Text + "','" + txtName.Text + "','" + txtCity.Text + "')"; cmd.ExecuteNonQuery(); } catch (Exception ex) { Response.Write("<script>alert("+ex.Message+")</script>"); } finally { con.Close(); } }
you can increment the id in table ,
click here
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