CODEWITHSUNDEEP
c#linqentity-framework
user3409204
user3409204

Reputation: 39

Show tables using entity framework

I am trying to show all the data of t1 table in a gridview using Entity Framework but I am getting an error

LINQ to Entities does not recognize the method 'Int32 ToInt32(System.String)' method, and this method cannot be translated into a store expression.

This is my code:

protected void Button2_Click(object sender, EventArgs e)
{
    var v = (from obj in de.t1
             where obj.Id == Convert.ToInt32(TextBox5.Text)
             select obj).ToList();
    GridView1.DataSource = v;
    GridView1.DataBind();
}

Upvotes: 0

Views: 80

Answers (4)

shredding
shredding

Reputation: 131

    protected void Button2_Click(object sender, EventArgs e)
        {
            var id = Convert.ToInt32(TextBox5.Text);
            var v = (from obj in de.t1
                    where obj.Id == id
                    select obj).ToList();
            GridView1.DataSource = v;
            GridView1.DataBind();
        }

Upvotes: 0

Edminsson
Edminsson

Reputation: 2506

protected void Button2_Click(object sender, EventArgs e)
{
    var objId = Convert.ToInt32(TextBox5.Text);
    var v = (from obj in de.t1
            where obj.Id == objId
            select obj).ToList();
    GridView1.DataSource = v;
    GridView1.DataBind();
}

Upvotes: 0

entropic
entropic

Reputation: 1683

The problem you are running into is the fact that the entity framework doesn't know how to translate Convert.ToInt32 into a valid SQL expression. Simply cast the textbox value to an integer before you query, and things should be fine.

protected void Button2_Click(object sender, EventArgs e)
{
    int id = Convert.ToInt32(TextBox5.Text);
    var v = (from obj in de.t1
             where obj.Id == id
             select obj).ToList();
    GridView1.DataSource = v;
    GridView1.DataBind();
}

Upvotes: 0

Yurii
Yurii

Reputation: 4911

Entity Framework is trying to execute Convert.ToInt32(TextBox5.Text) on the SQL side, which it obviously cannot do.
So, introduce a temporary variable to store the result of conversion: 

var tempId = Convert.ToInt32(TextBox5.Text);

Then pass it to the where clause: 

...
where obj.Id == tempId
...

Upvotes: 3

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